PHP Fatal error: Cannot redeclare class - high traffic.

Hi List, First post, hope this is alright :) I'm running: Windows Server 2003, IIS 6.0, PHP 5.1.4 (ISAPI), AMFPHP 1.2.5, MySQL 5.0.24. The box is getting a *lot* of hits. A gateway PHP file is being called about 1,000,000 times per day. I've got error logging enabled, and I find there's a lot of: "PHP Fatal error: Cannot redeclare class encrypt" This is not the gateway, but another file that is called a lot. I've been assured by the coder, who has checked the code time and time again that it is *not* a problem with his code. The problem only seems to occur when the server is at peak load, with the file perhaps being called 40 times a second. Has anyone encountered this on a similar setup? I'm also getting quite a few " PHP Fatal error: Maximum execution time of 60 seconds exceeded " on mysql_connect statements, but this appears to be a separate issue, which i'm also looking into. Thanks for any advice, cheers iestyn