The can't communicate w/williams is a known bug.
One play, I hit williams BEFORE, I did sentinel island, WAY before -- I was about level 8-9, (going from memory, was a few months back) they were about 8-10 levels over me). It gives a warning about not going up against them if you are too low: I was killed several times till devised strategy (an extreme example of hit&run): go in under hide-in-shadow, summon undead & throw a damage, then run out -- wait for regen, save game, repeat. Had to save game each time, since 1-hit and they could kill me.
Now, they've changed it -- locked the doors so you can't get in no matter what until the "time is right" and the whole place is poisoned, which is really messed up. I didn't complain about that being hard (I've complained about other things being hard when they are!), but that one -- I was warned, and I was doing it out-of-sequence, so I was willing to take my chances (I was 'playing'!)
Now, playing has been made *illegal* and the option appears to be disabled.
As it is now, I've had it go both ways -- once, prepatch-- williams would never acknowledged I'd cleared the place (so no key), but then got a first patch about ~1-2 months ago, and when I played through again it all went fine.
So if the patches don't fix it, you may have to play it through again.
It's unfortunately that took out the option to throw yourself at them before becoming a dragon. I don't understand why they'd do that when they *gave* a warning! (which is still in, but now is rather meaningless, since you can't encounter the black ring elite, until you go back ... and the limitation is purely bogus -- since all doors are locked, now, (all 3 levels checked via jump-access), but in dragon form, no locks encountered.
Sorry no better help, but replay may be your best option....
