Crystal Reports Problem with CSV Connectivity

I have a report that works fine using ODBC to a SQL Server set of data. I now need to modify the report and link to a CSV file that will supply an additional set of data. I have created an ODBC to the CSV file; Have included it into the Report and done a LINK in the Database Expert. All of the fields now show in my Field Explorer. BUT - if I try to Drag a field to the report it doesn't move across; Also tried to create a new subreport - and can't select; Even tried a Formula - and add a field to it - but won't let me select. Any ideas would be very helpful. \phil