I have a problem with a select statement... I don't know if its ODBC driver or what...

Before executing a statement sent via ODBC, I copy the value into a temp table for later analysis so I can track down errors but can't find any with the following sample. If I paste the command in the ISQL window and execute, it works no problem....

select
     TmpTran = XProcID.ta_transno,
     XProcID.ta_procID,
     XDiagID.ta_catid,
     Cats2.ca_epidays,
     Cats2.ca_cap,
     Cats2.ca_fySnap,
     BadCat = case
              when XDiagID.ta_catid = Cats2.category
                  then ' ' 
              else 
                  '*'
              end
  into
     tempdb.dbo.tmpjoin1
  from
     tempdb.dbo.XProcID,
     tempdb.dbo.XDiagID
           left outer join tempdb.dbo.cats2
           on XDiagID.ta_catid = Cats2.category
  where
     XProcID.ta_transno = XDiagID.ta_transno

Any input would be appreciated... This is really getting to be a PITA since it is not consistent (results). The tables are only 2-3 fields each, and only 300,000 records (small data size) and I have the tempdb database allocated for over 1 GIG of space so I know that isn't the problem...