I received the exact same error after installing Prat, ORA2, Bartender and a few other recent Ace2 addons two nights ago. There's obviously a conflict with various Ace-OO instantiations so I just deleted all Ace-00 folders in each of the mods' /libs folders. I installed the Ace2 library stand alone package at the Addons folder and all boot up fine now.
I know each Ace mod is supposed to operate with it's full set of libraries embedded. Can we pinpoint it down to the particular mod that might be causing this?