Error: CrystalDecisions.CrystalReports.Engine.FormulaException: Error in File C:\DOCUME~1\

Hello,

I am having a crystal report using datastored in a dataset. When I select one of items in a dropdownlist, it gives me this error message. Note that I used that code before in another web page using a different crystal report and a different dataSet and it worked successfully, but this time it doesn't work...anyone can tell me what causes this error and how to solve it?

NOTE: I am using a vb code behind in my .aspx page

Error in File C:\DOCUME~1\AM-TK-~1\ASPNET\LOCALS~1\Temp\temp_03ca344b-568e-4ea1-bea8-94f3ef92bbcd.rpt: Error in formula <Record_Selection>. '{StProd2.ItemDescription}' The result of selection formula must be a boolean.

Description:An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details:CrystalDecisions.CrystalReports.Engine.FormulaException: Error in File C:\DOCUME~1\AM-TK-~1\ASPNET\LOCALS~1\Temp\temp_03ca344b-568e-4ea1-bea8-94f3ef92bbcd.rpt: Error in formula <Record_Selection>. '{StProd2.ItemDescription}' The result of selection formula must be a boolean.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[FormulaException: Error in File C:\DOCUME~1\AM-TK-~1\ASPNET\LOCALS~1\Temp\temp_03ca344b-568e-4ea1-bea8-94f3ef92bbcd.rpt:Error in formula <Record_Selection>. '{StProd2.ItemDescription}'The result of selection formula must be a boolean.]  . F(String  , EngineExceptionErrorID  )  . A(Int16   , Int32   )  . @.(Int16  ) CrystalDecisions.CrystalReports.Engine.FormatEngine.GetPage(PageRequestContext reqContext) CrystalDecisions.ReportSource.LocalReportSourceBase.GetPage(PageRequestContext pageReqContext) CrystalDecisions.Web.ReportAgent.u(Boolean  N) CrystalDecisions.Web.CrystalReportViewer.OnPreRender(EventArgs e) System.Web.UI.Control.PreRenderRecursiveInternal() System.Web.UI.Control.PreRenderRecursiveInternal() System.Web.UI.Control.PreRenderRecursiveInternal() System.Web.UI.Page.ProcessRequestMain()

Dear Frnd',

It will nice if you provied more info, like in drop you are selecting which report to get or some value on which parameter it get the dataset.

or what are the datatype in database & on report.

Some more detail need to get it root.