data access problem...

Hi, I have a quite strange problem with PHP/MySQL. I wrote some scripts for an user database and it's working fine so far. Today I implemented a script to change the details of a user. That's working as well. But after doing the update I can't access to the changed row anymore with that script. I checked the databse with PHPMyAdmin and the update was done correctly and I can even access it without problems. But not with my script. It isn't even possible to log in with that user any more. What could be a possible reason for that. If you need to see the code just tell me. I get no error messages but the timeout from the browser. TIA, Michael