How to develope an error-handler for a kind of replication

Hello,
I use postgresql 7.0.2 as backend and MsAccess as frontend. In order to improve performance I use local Access tables and a copy of these tables on postgresql side. This means, that when I update some rows in the Access tables I have to synchronise the server tables and to develope an error-handler for any cases. In the docu I read, that every SQL query is executed in a transaction, this means that every update or insert is completed or isn't done. Now I assume, that an error occurs, because the server has some problems, or the network or, or, or.....How can I find out on Access side, wheter the transaction was made or not? Did the error occur befor or after the transaction?

Please, can someone show me, where I can find some information, hints, examples,.... how to realize this Error-handler ?

Thanks for your help
Irina
E-Mail: i(dot)hasenoehrl(at)aon(dot)at