Eh? Your PS3 account won't work for the PC version? This doesn't make sense. If you buy the game, you activate the account, which should allow you to play on whichever platform, regardless of which system you purchased the copy for(e.g. WoW account works on both PC/Mac)

This would make sense if multiple players could login and use a single account at the same time, but the game does not work that way. If you login from the PS3, it would kick you off the PC.

Seriously, I'd like to know the reasoning for this. I was able to download the PC client before I even purchased the game. I couldn't play because no active account, but I had the game ready and waiting.