Something funked up A6 - that is a Forbid() (or is it Disable() - can't remember) using an A6 register that has wandered off into Lala-land.
The code dump shows it reads the register in from memory, which probably means something has stomped over it.
Try adding Mungwall to the mix and see if it triggers something more? (Sorry if I missed out on you already doing that.)
(The ultimate debugging tool for cases like this is, for me, BDebug in history mode.)
