S1010 function sequence error after ODBC-driver-upgrade

Hello!
 
We upgraded the PostgreSQL-ODBC-drivers on our webservers last friday;
installed version before the upgrade was 7.3.100, I upgraded to 7.3.200.
We've got PostgreSQL 7.3.4 running on linux-servers; the ODBC-driver ist
used on Windows 2000 Server, running IIS or Apache 2.0 and ColdFusion
5.0.
 
Since upgrading, we very often get ODBC Error Code = S1010 (Function
sequence error). This happens on some (but not all) tables when
attempting to do several UPDATEs or DELETEs in one script. The error is
persistent - it doesn't help to restart the server; VACUUM ANALYZE on
the same table works flawlessly, so does doing the exact same queries
via PGAdminII (not so very recent version and thus older ODBC-drivers,
too).
 
When creating a new table, inserting a dozen rows or so and then trying
updates or deletes on this table in a ColdFusion-script, everything
works just fine, so we cannot willingly reproduce the symptoms on any
more than the affected production-tables.
 
I read up on the subject of S1010 a bit and I found suggestions that one
reason might be "SQLExecute" being called before "SQLPrepare". I
installed the new PostgreSQL-ODBC driver via control panel and
reinstalled 7.3.100 on one server - but that didn't help at all. I don't
know if uninstalling an reinstalling the old version does provide pro a
"clean" rollback of all ODBC-driver-components to the previous version -
so I'm not sure, if not some remains of the 7.3.200-install do still
cause this problem. 
 
I am absolutely sure that we didn't change anything else but this
ODBC-driver-update on our webservers since before the errors occured
until first occurrence - no Windows Update, no ColdFusion-Patches, no
changing of any settings.
 
Could you give me some hints as to where and what to check next and
maybe how to assure a complete removal of any system-changes the update
might have caused?
 
Thank you very much!
 
Regards
 
   Markus Wollny