Problem with extensions in PHP4.3.1

Hi folks, we just upgraded to the newest PHP from 4.3.0. I´m a little bit surprised because of the manual saying that this should be a security fix only. Unfortunately, serveral extensions fail to work. PHP 4.3.1 is running with IIS5.0 (no comments on that please). Runing as a CGI. with version 4.3.0 everything was fine. After the upgrade extensions CURL and MSSQL fail to work. The failure is that no page is returned, the process is then stopped after 300 seconds by IIS with a timeout error. The ini points to extension_dir = c:\php\extensions\ where the extensions reside. Moving the "faulty" extensions to then system32 dir does not help either. Am I doing anything wrong?! Regards, Chris