problem since upgrade php/apc

[Technique Facosteam <tech.facosteam@gmail.com>]

Hello,

I made apt-get upgrade yesterday evening, and since I've got this 
message in my logs :

PHP Warning:  Cannot load module 'XCache' because conflicting module 'apc' is already loaded in Unknown on line 0

Can someone tell me how to locate the application which make the conflict to resolve the problem ?

Thanks by advance.

Sebastien

PS : I'm on Debian Etch with apache 2.2.3-4+etch6, php 5.2.9-0.dotdeb.0