I got this error when starting php5-fpm service. I am using Debian Squeeze with dotdeb.org repositories to get php5-fpm package for php 5.3.
In this case the error was related to APC package mismatch between debian and dotdeb.org repositories. To solve the problem I uninstalled php-apc from debian repositories and installed php5-apc from dotdeb.
# apt-get remove php-apc # apt-get install php5-apc