Your wealth of knowledge is astounding.

I checked my Word version in the Help menu, and I have Service Pack 3 even. Not a firm believer in the robustness of Microsoft's operation, I refused to give MS the benefit of the doubt and personally went to see the registry under HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\W ord\Options.

Surprise! (Well, actually I wasn't surprised.) There was still no AlternateRevisionStepThrough key in there. I have no idea what transpired when Service Pack 3 was installed, but the key must have been removed some time ago if Service Pack 2 had ever installed it.

Anyways, I've manually inserted the key, as instructed by the Knowledge Base, and the problem is gone!

Thanks so much!