Ok... I think that led me in the right direction.
I think my main problem is interpreting the error msgs.
See my log file now... this first entry is when the group was not populated:
Code:
GroupAdd('MOR6H1', 'Power Users', 'BHC-NA\Domain Users')
The operation completed successfully.


That looks good, of course. If I run it again, though, it would be nice to get a friendlier message than the following:
Code:
 
C:\JOBs>kix32 lclgrpmodder
GroupAdd('MOR6H1', 'Power Users', 'BHC-NA\Domain Users')
COM exception error "Add" ((null) - (null)) [-2147352567/80020009]



In the above case it would be nice to see a "The user/group is already a member of the local group" or something similar.
Beggers can't be choosers, though, I suppose. Any other suggestions?