Server error and deadlocks

Newbie here...

We have a web app with a MySQL (ISAM) db server and we're wanting to port
and run it on PostgreSQL. We've got data in PostgreSQL and code running
under Mercury Interactive "LoadRunner" but I'm seeing these messages on the
server:
------------------------------------------------------
WARNING: COMMIT: no transaction in progress
LOG: pq_recvbuf: unexpected EOF on client connection
ERROR: deadlock detected
ERROR: deadlock detected
ERROR: deadlock detected
. . .
------------------------------------------------------
Seems to me like commits are being made when there's nothing to commit.
There's gotta be some overhead here so I'm thinking unnecessary commits
should be removed from the code.

Also, on the EOF on client connection messages I'm thinking the cgi code
should explicitly disconnect. Does it matter?

Finally, there are LOTS of deadlocks and I'm thinking it's because they are
not doing "SELECT ... FOR UPDATE" or are explictly locking tables. Or they
are constantly updating the same rows. It seems our duhvelopers need to get
up to speed on transaction management with PostgreSQL. Any suggestions on
how to get them to do PostgreSQL transactions and wean them off MySQL ISAM?

TIA!!!!!!!!
db