Thank you again MortysTW for your help.
I did the REPAIR and OPTIMIZE as you suggested, but that didn't help.
I finally gave up. LOL.
I reinstalled my test forum, upgraded to vB 3.6.8 and vBAdvanced 2.0RC2. But I stopped short of updating ibProArcade. If I don't update to the newest version of ibPA (but stay at 2.6.1) I don't receive any errors.
Must be something with vB 3.6.8, vBAdvanced 2.0 and ibPA 2.6.3, or a combination of the 3.
Anyway, your help is appreciated. And my apologies to those who might be reading this thread looking for an answer.
BTW, if this could be figured out, I'd like to keep my arcade current.
Maybe when MrZeropage as a spare couple of minutes

he can look into it.