Getting error in SetDataSource

[sundarp]

Error description: Message:Object reference not set to an instance of an object.
Source:mscorlib
Target:Void StructureToPtr(System.Object, IntPtr, Boolean)
Stack: at System.Runtime.InteropServices.Marshal.StructureTo Ptr(Object structure, IntPtr ptr, Boolean fDeleteOld)
at CrystalDecisions.ReportAppServer.DataSetConversion .DataSetConverter.Wrap(DataSet dataset, CrdbAdoPlusDelegate& adoPlusDelegate)
at CrystalDecisions.CrystalReports.Engine.Table.SetDa taSource(Object val)

My reports works fine except few times.

It is getting crash due to the exception. Please guide me have to solve the above problem.

Thanks in advance.