It looks like the problem lies here: http://support.microsoft.com/default.aspx?scid=kb;EN-US;q195956
...as this KB article has to do with modifying that password for the account that is being used by the Web Application Manager (WAM)in the IIS metabase.

But I still don't understand IIS metabase administration well enough to know exactly what to do to fix the problem described in my initial message on this thread. But I _think_ the problem simply involves changing the account that is being used for the Web Application Manager (WAM)in the IIS metabase.

If the problem _does_ in fact involve this issue, can any of you webmasters tell me how to make the change?