CHECKPOINTS.

Hello.

I have a problem with the transacctions. I'm using postgres 7.1.3
Our program connects with the database, then it starts the transacction
with:

EXEC SQL BEGIN;

but in the first SELECT I obtain the next error:

Error: -603
Begin: already transacction in progress.

I have tried to put:

EXEC SQL ROLLBACK;
before the BEGIN, but postgres says me that there isn't any transacction
in progress.

Can you help me?
Thanks.