The Associations area under Classes Cleaner is where all my trouble existed.
RegVac found 14 entries under that scan. Seven of them finally ended up in the cantremove text file.
Of the seven remaining, it removes only one.
The other six are:
HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\shell
HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\Shell\Bags\1\shell
HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\Shell\Bags\18\shell HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\Shell\Bags\24\shell HKEY_CLASSES_ROOT\Local Settings\Software\Microsoft\Windows\Shell\Bags\25\shell HKEY_CLASSES_ROOT\mapi\shell
HKEY_CLASSES_ROOT\Microsoft.PhotoAcqDropTarget.1\shell

The one key it will remove is
HKEY_CLASSES_ROOT\csc\shell
It is recreated every time it is removed, so not much point in removing it.

I added the other six entries to the can't remove list and ran the program with no problems. [284 items removed]
Problem seems to be solved for my computer. Whether it will work on all Vista computers is an open question. Looks like Vista doesn't want its associations messed with.

   That is strange.  I have tested this in two different versions of Vista and it does not do that to me.
   Those entries are removed because they are blank and so they serve no purpose.
   The latest version of RegVac (v.5.01.01) skips those entries when it is running in Vista.
   Thanks for your help in figuring this out.
   If anyone else finds any entries which cause this problem, please post the entries in this forum.