I have Windows 2003 Webserver with Apache 2.2.23 and php 5.3.18 VC9 ts on the boart. When I add php_apc 3.1.9 extension, it works over an hour and shuts down Apache. I can only restart apache with stop and start buttons on Apache Monitor, because restart button popups error message and fails Apache. New beta versions of apc don't work, neither does older. Maybe new version of php conflicts with apc? I have no other idea.
Most often reason to happen such error is if you have PHP Thread safe and you trying to set not tread safe extension or opposite...
Get both thread safe and non thread safe apc extensions and try to run your apache with each of them..