can't export to pdf

 Hi I'm having problems exporting to pdf and get the following error message:
 
"Adobe reader could not open filename[1].pdf because it is either not a supported file type or because the file has been damaged"
 
I'm using VS2008 and here is my code to export data to PDF:
 
lNUTHState.ExportDataCollection = lResultCollection
Session( dtaFinal.DataSource = lResultCollection
dtaFinal.DataBind()
 "lNUTHState") = lNUTHStateDim dtaFinal As New DataGrid()


dtaFinal.HeaderStyle.ForeColor = System.Drawing.Color.White
dtaFinal.HeaderStyle.BackColor = Syste ...