JDBC and commit problems

I'm trying to roll a JDBC intensive application utilizing PostgreSQL and
I came across a very difficult (and annoying) problem.

The long and the short of it comes down to it appears that doing manual
transactions do not appear to work presently under postgres. Switching
the application to use autoCommit() cleared up the problem.

I'm utilizing 7.2.2 for the database and grabbed devpgjdbc2.jar a couple
days ago to test against, though I had similar issues with other
versions of the jdbc driver.

I've searched quite a bit and can't find any mention of others having
this problem. Does everyone normally autocommit? Regardless, I have
reasons where wanting full control over my transactions would be highly
desirable and would like to either know what it is I'm doing wrong, or
if this is indeed a flaw in the jdbc driver.

Regards,

Robert M. Zigweid