I have installed \'WampServer2.1e-x32\' stack with addon version of php 5.2.11 . I downloaded apc3.0.19.dll and placed under the directory and required information in php.in
Looks like recent builds in windows.php.net are broken too. I've tested:
both from http://windows.php.net/downloads/pecl/releases/apc/, and both had this problem.
If you are stuck on this like I was, go to: http://downloads.php.net/pierre/
And download php_apc-3.1.10-5.4-vc9-x86.zip.