annihilatus666, if you downloaded the version with the prc already installed, it might simply be an issue of the mod using an older version of the prc while you have the newer files.
I always tried to make sure EN4 and EN6 would work fine by installing the PRC on the base module, and last I checked (a few version of the PRC ago), that worked perfectly fine. So you could try downloading just the base mod (the CEP 2.0 one) and installing the PRC onto it.
I was going to download and install the new PRC but it seems it didn't like the fact that I simply copied NWN off my external drive. Dunno if I actually wanna reinstall and repatch everything, but perhaps I could hunt down the regkeys it wants.
BTW, EN4 and EN6 both play very differently. EN4 had a very random magic system where it was possible to get uber fast, but you'd need it by end game. EN6 I designed around the idea of having a one death and your out system and a low magic system that was more geared towards the level of the character. So if you can't get EN6 to work, you can always try EN4.