Bug in "Staff of starlight" ?
 

I'm stack in "Staff of starlight" mission. After talking to 3 mages in Arlania , I went to activate those three ancient altars, but the shield of tower of archmage Rezo didn't disappear but the mages are disappeared. Did I miss something to deactivate the magic shield? Quest log shows "Pay a visit to the Tower of Archmage Rezo". Must to pay something to someone ? I reloaded the game and changed the order of activating altars but the shield is still there. Also I've explored whole 10 knoweth kingdom.
So, the next step should be ending the "Staff of starlight" and then go back to Greenwort to "Demonis through the portal at the palace square...". Right !
So, what is wrong ? What I didn't ?
Should I start the game again, from the begining to supose that the bug is fixed ?
Sorry for my bad english and thanks in advance.
http://img339.imageshack.us/img339/7327/game1m.jpg
http://img402.imageshack.us/img402/8171/game2p.jpg

Yeah this is a strange bug. I've gone through 3 playthroughs with different patch levels and never had this problem. :(

If you restart, it should be fine. Sorry. :(