Remove the Retainer, Take it back to Auction House. This was a bad idea to begin with, and the original development team should have realized this.

Auction House is supposed to be simple like it has been in EVERY other MMO.

P.S. To Original Poster, I also can't put my retainer up, this sucks but we'll just have to deal until they change the system. The development team is hard at work on my important things. Not saying this isn't a problem, It's just a minor one.