PHP script give error 500 after 20-30 seconds

[vexx]

I have a PHP script that updates a lot of tables in one of my websites. The script runs fine on other machines, but on this one, after 20-30 seconds, it gives me 500 Internal Server Error. There is nothing in the logs, my guess is there is some kind of timeout set wrong...i've checked both PHP and Apache's timeouts..everything looks ok

 

Do you have any other advices..what settings to try? What server configuration might cause this?

 

Tnx in advnace