Sort on TimeStamp field not working

Hello,

If I use the following SQL statement with a TSQLQuery component, my result
set is not sorted properly:

  SELECT * FROM calls
   WHERE case_id = 5055
   ORDER BY call_start DESC;

call_start is of type 'timestamp'.  

This exact same query in psql, or pgAdminII, yeilds a properly sorted result
set.

If I use the ODBC driver with ODBCExpress component suite, I
aslo get a properly sorted result set.

Why am I not getting a properly sorted result set when uing dbExpress?

Using:
Delphi7
PostgresSQL 7.3.2
dbExpress driver is pgExpress v2.00

Thanks,
Chuck