Expression model is undefined on line 56, column 77 in product/productHead.ftl.
The problematic instruction:
----------
==> if model.days?exists [on line 56, column 72 in product/productHead.ftl]
 in user-directive ww.form [on line 53, column 9 in product/productHead.ftl]
 in include "../product/productHead.ftl" [on line 16, column 1 in group/shopDetail.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression model is undefined on line 56, column 77 in product/productHead.ftl.
	at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)
	at freemarker.core.TemplateObject.invalidTypeException(TemplateObject.java:134)
	at freemarker.core.Dot._getAsTemplateModel(Dot.java:78)
	at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
	at freemarker.core.BuiltIn$existsBI._getAsTemplateModel(BuiltIn.java:636)
	at freemarker.core.BuiltIn$existsBI.isTrue(BuiltIn.java:647)
	at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:77)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.Environment.visit(Environment.java:233)
	at freemarker.core.UnifiedCall.accept(UnifiedCall.java:116)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.Environment.include(Environment.java:1378)
	at freemarker.core.Include.accept(Include.java:155)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:196)
	at freemarker.core.Environment.process(Environment.java:176)
	at freemarker.template.Template.process(Template.java:232)
	at com.opensymphony.webwork.views.freemarker.FreemarkerResult.doExecute(FreemarkerResult.java:153)
	at com.opensymphony.webwork.dispatcher.WebWorkResultSupport.execute(WebWorkResultSupport.java:143)
	at com.opensymphony.xwork.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:311)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:206)
	at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:168)
	at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:115)
	at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.webwork.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:171)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:151)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at net.jlibrary.interceptors.ExceptionInterceptor.intercept(ExceptionInterceptor.java:42)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
	at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:113)
	at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:225)
	at com.opensymphony.webwork.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:202)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:39)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at com.opensymphony.webwork.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:88)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	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:61)
	at java.lang.Thread.run(Thread.java:745)