shrubmod isn't really a admin utility, but I guess I know what you mean.
You want to give users/groups privileges, right?
If so, then you need a Mod which supports the mighty -so called- shrubbot ;)
These Mods:
NoQuarter,
ETPub and
Jaymod, do support the shrubbot
(I can't say if etpro also supports shrubbot, but i guess not)
And you can also use etadmin_mod on a windows server (remember etadmin_mod isn't really a standalone-mod, its just an "enhancement" to the mods above), but you need cygwin.
Here's a documentation for etadmin_mod on windows machines.