note 21536 rejected from ref.pgsql by torben

I use postgresql 7.0 et php and I meet a problem with the transaction. For example, with postgres and pgacces only, I begin a transaction which contains 2 requests. I execute only the first one and i don't finish the transaction (no commit). Finally, the transaction is rollback and the request is canceled. When I execute the same with Php, the first request is commit while no commit is executed explicitely. Perhaps, I must open the connection by changing an autocommit mode ? Any idea ? thanks