fifth reinstallation works
I installed Sculptor3 on another computer last night, and installation went seamlessly, no problems. Bolstered by this victory/defeat, I went back to the original computer, uninstalled 2.05 once again, reinstalled 3.0 again, and got the familiar errors immediately after activation.
I then renamed the winfilecache, and restarted dreamweaver.
At this point, no glitches.
I have no idea what makes this round of uninstalls and reinstalls different than the others, it's the same procedure. I'm going to have to start counting to 100, or six in this case, before I write to the forum.
Moral of the story for me: resetting the winfilecache does seem to correct most interface problems with webassist extensions. Here's the moral: repeat the process more than once, keep trying, apparently some resets and reinstalls are different than others.
Thanks for your time.