Jochen,

According to email from Ruud the Win9x should be able to decern GLOBAL groups without KXRPC.

Chris,
When you say logon Domain, all NT/2000 systems appear to work okay with this INGROUP call?

How about making a different test case.

Make a GLOBAL group named TESTING
and add the account you want to try into this group. Then logon to this Windows 9x system and rename all of the *.PWL file in %windir% to *.PW_ and verify that system is logged onto the network.

Don't even try mapping for now. Create a test script called MYTEST.KIX and copy it to this Windows 9x system locally along with the KIX32.EXE and KIX .DLL files, all in the same C:\TESTING folder.
Then at a DOS prompt:
c:\testing> KIX32.EXE MYTEST.KIX /F

code:
IF INGROUP("TESTING")
  ? "User was found"
ELSE
  ? "User not found"
ENDIF
? @ERROR
Let us know what happens here.