Crystal report error.. Please help

Any body has any idea about his error please?

I got this error at the time of creating crystal report. I tried
everything to resolve this error. But I could not. Please help.

Exception has been thrown by the target of an invocation. at
System.Reflection.RuntimeMethodInfo.InternalInvoke(Object obj,
BindingFlags invokeAttr, Binder binder, Object[] parameters,
CultureInfo culture, Boolean isBinderDefault, Assembly caller, Boolean
verifyAccess) at
System.Reflection.RuntimeMethodInfo.InternalInvoke(Object obj,
BindingFlags invokeAttr, Binder binder, Object[] parameters,
CultureInfo culture, Boolean verifyAccess) at
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags
invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Microsoft.VisualBasic.CompilerServices.LateBinding.FastCall( Object
o, MethodBase method, ParameterInfo[] Parameters, Object[] args, Type
objType, IReflect objIReflect) at
Microsoft.VisualBasic.CompilerServices.LateBinding.InternalL ateCall(Object
o, Type objType, String name, Object[] args, String[] paramnames,
Boolean[] CopyBack, Boolean IgnoreReturn) at
Microsoft.VisualBasic.CompilerServices.LateBinding.LateCall( Object o,
Type objType, String name, Object[] args, String[] paramnames,
Boolean[] CopyBack) at
SentryDotNet.ReportComponents.ExportFunctions.ExportPDF(Stri ng
ExportFilePathName, Object& crReportDoc)

ExportPDF has the following code

ExportPDF(ByVal ExportFilePathName As String, ByRef crReportDoc As
Object)

Dim crExportOptions As ExportOptions
Dim crDiskFileDestinationOptions As
DiskFileDestinationOptions

'Set the options for saving the exported file to disk
crDiskFileDestinationOptions = New
DiskFileDestinationOptions
crDiskFileDestinationOptions.DiskFileName =
ExportFilePathName


'Set the exporting information
crExportOptions = crReportDoc.ExportOptions
With crExportOptions
.DestinationOptions = crDiskFileDestinationOptions
.ExportDestinationType =
ExportDestinationType.DiskFile
.ExportFormatType =
ExportFormatType.PortableDocFormat
End With

'Export the report
crReportDoc.Export()

THis has been working good. The only change I have added is including
2 new columns in XSD file and also on the report, SQL query. SQL query
is working fine and returning results.

But when I am trying to create PDF crystal report using the above
ExportPDF function. It thrown error.

Any help please?

THanks.