I posted somehting similar to this on the SOE tech forum, but I can't read that from work so I'll ask for feedback here too...maybe someone already experienced and solved this...
I just completed Oceangreen Theme progression with the final Blackburrow task. I can now zone into Void B and when I talk to the PoK merc vendors they will offer me Tier II mercs.
However, after dismissing my existing mercs (3 chars/accounts on 2 different PCs) I have the exact same issue with all of them: Either I get a message saying I already have a Mercenary Purchase Pending, or I get a merc window pop up but no merc. When I click the Info tab for the merc window it gives an error message concerning DB String 0-23.
I tried zoning, camping, and ultimately camping to desktop, and none of these make the issue go away. Right now I cannot buy any mercenary at all on any of these characters.