Data Report Problems

For the first time when I execute this (that is by datareport.show method) this is working fine.

Private Sub DataReport_Initialize()
If DataEnvironment1.rsLandLordConList_Grouping.state = adStateOpen Then
DataEnvironment1.rsLandLordConList_Grouping.Requery
DataEnvironment1.rsLandLordConList_Grouping.Filter = "`Plot No` >= '1'"
End If
End Sub

but if I close the report and try to give datareport.show once again then, I am getting the following error in this filter statement

DataEnvironment1.rsLandLordConList_Grouping.Filter = "`Plot No` >= '1'"

runtime error 3001

The application is using arguments that are of the wrong type, are out of acceptable range, or are in conflict with one another.

Please help me


Regards
Nakheel