ERROR: cursor 'xxx' does not exist

I had a problem with a program that load about 2 MB of information from
de DB with a rate of data transfer about 80K. I don´t know why the 'top' of
80K, but is not harware. I still have this problem.
Then I set the "Use Declare/Fetch" opcion on the ODBC. This opcion take
the information to transfer from 2MB to about 100K. But I have a BIG
problem, this opcion activate the use of cursors and the use of commit and
rollback. The problem is that I get the message 'ERROR: cursor "xxx" does
not exist' when it makes the close cursor (I see this on the CommLog of
ODBC), but the cursor was declared previously. The really problem is
'ERROR: current transaction is aborted, commands ignored until end of
transaction block' because of cursor's problem. Since I set the "Use
Declare/Fetch" the ODBC use transactions (BEGIN,COMMIT,ETC).
I do not want the use of transactions. Can I use Cursors and 'Disable'
Transactions ?. I'm using postgresql 8.0 windows native.

Nuno Goncalves