Somehow Symfony2 Standard (2.0.0) have a bug on the installer that produces an error while it checks APC version. (even if you don't have it installed it, APC is NOT a requirement for SF2)
Here is the patch to fix it:
http://pastebin.com/raw.php?i=dwaM0uCC
Btw, This patch has already been commited to SF git, (not yet released).