FreeMarker template error (HTML_DEBUG mode; use RETHROW in production!)

The following has evaluated to null or missing:
==> param  [in template "WEB-INF/views/_Layout/program/inc/inc.Header.ftl" at line 9, column 6]

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Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
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FTL stack trace ("~" means nesting-related):
	- Failed at: #if param.mode! == "organ_markup" || ...  [in template "WEB-INF/views/_Layout/program/inc/inc.Header.ftl" at line 9, column 1]
	- Reached through: #include "/WEB-INF/views/_Layout/prog...  [in template "WEB-INF/views/_Layout/program/core/coreHeader.ftl" at line 40, column 1]
	- Reached through: #include "/WEB-INF/views/_Layout/prog...  [in template "WEB-INF/views/_Templet/Layout/layout_dept/layout_dept.ftl" at line 6, column 5]
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Java stack trace (for programmers):
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freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]
	at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134)
	at freemarker.core.UnexpectedTypeException.newDesciptionBuilder(UnexpectedTypeException.java:85)
	at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:48)
	at freemarker.core.NonHashException.<init>(NonHashException.java:49)
	at freemarker.core.Dot._eval(Dot.java:48)
	at freemarker.core.Expression.eval(Expression.java:83)
	at freemarker.core.DefaultToExpression._eval(DefaultToExpression.java:88)
	at freemarker.core.Expression.eval(Expression.java:83)
	at freemarker.core.EvalUtil.compare(EvalUtil.java:113)
	at freemarker.core.ComparisonExpression.evalToBoolean(ComparisonExpression.java:62)
	at freemarker.core.OrExpression.evalToBoolean(OrExpression.java:36)
	at freemarker.core.IfBlock.accept(IfBlock.java:49)
	at freemarker.core.Environment.visit(Environment.java:330)
	at freemarker.core.Environment.visit(Environment.java:336)
	at freemarker.core.Environment.include(Environment.java:2582)
	at freemarker.core.Include.accept(Include.java:171)
	at freemarker.core.Environment.visit(Environment.java:330)
	at freemarker.core.Environment.visit(Environment.java:336)
	at freemarker.core.Environment.include(Environment.java:2582)
	at freemarker.core.Include.accept(Include.java:171)
	at freemarker.core.Environment.visit(Environment.java:330)
	at freemarker.core.Environment.visit(Environment.java:336)
	at freemarker.core.Environment.process(Environment.java:309)
	at freemarker.ext.servlet.FreemarkerServlet.processEnvironment(FreemarkerServlet.java:910)
	at freemarker.ext.servlet.FreemarkerServlet.process(FreemarkerServlet.java:879)
	at freemarker.ext.servlet.FreemarkerServlet.doGet(FreemarkerServlet.java:764)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:529)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:623)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:64)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:641)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:415)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:347)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:284)
	at org.apache.tiles.servlet.context.ServletTilesRequestContext.forward(ServletTilesRequestContext.java:241)
	at org.apache.tiles.servlet.context.ServletTilesRequestContext.dispatch(ServletTilesRequestContext.java:222)
	at org.apache.tiles.renderer.impl.TemplateAttributeRenderer.write(TemplateAttributeRenderer.java:44)
	at org.apache.tiles.renderer.impl.AbstractBaseAttributeRenderer.render(AbstractBaseAttributeRenderer.java:106)
	at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:670)
	at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:690)
	at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:644)
	at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:627)
	at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:321)
	at org.springframework.web.servlet.view.tiles2.TilesView.renderMergedOutputModel(TilesView.java:112)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1286)
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1041)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:529)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:623)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:200)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at centum.filter.NoCacheFilter.doFilter(NoCacheFilter.java:23)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at centum.filter.HTMLTagFilter.doFilter(HTMLTagFilter.java:23)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at centum.filter.HttpsFilter.doFilter(HttpsFilter.java:21)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:71)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:169)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:596)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:670)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346)
	at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:424)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:928)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1786)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
	at java.lang.Thread.run(Thread.java:750)