ODBC drive strange behavior

Please help!

The PSQLODBC aborts a transaction with a strange error while execute a
legal query.
The message is:

"Could not begin a transaction; unexpected protocol character from
backend (sen_query) (#1)"


I tried the same query with psql client and it works with no problems.

Does anyone know what this message means ?

My configuration:

Data base server: PostgreSQL v6.5.2
OS server: Linux 2.0.37 (Debian)
Win Client: M$_Access95
PsqlODBC v6.40.0006
log file attached.

Any help would be very apreciated.

José