Hi!
I can take custom Classes (Dragon Shaman etc.) with my character but not Dark Flame Zealot PrC even though I met the pre-reqs.
Added the level 1 and ready to get to level 6 .bic. Here's all the infos I could gather:

-Playing SoU module.
-Tested the build leveling from 1 to 7 on a custom module leveler (Ravenloft, beyond the gates) and it worked (same bic used than with starting the SoU character).
-Tested importing my level 6 character meeting the pre-reqs for Zealot into the Ravenloft module to level up in it: could not take the Zealot PrC at level 6... neither 7.
- In both cases I could take the Assassin PrC (and could take Swift Wing PrC at level 7 on Ravenloft), telling me it's not an alignment or skill bug imo, neither a *unable to take PrC classes bug.

- All of this lead me to believe it might be the "Weapon proficiency: kukri" feat causing all the fuss since the pre-req states "Exotic weapon proficiency: kukri"... Maybe for some reason the feat does not register correctly as a pre-req only while on an official module..?

Well, I don't know what else I could say... Added the lvl 1 .bic made with the character creator and a .bic with the character ready to level up and take the PrC. 

If there is a way to get around this while editing the Zealot and removing the pre-req while keeping the game, would be nice (I'm just no modder so I don't know how... would need to tell me how or just zip back the modded PrC.)

I built this character specifically for this PrC and don't feel like restarting another :-(, any help would be greatly appreciated, thanks alot!