mock 0.8.9 will not build anything

[Frank Büttner]

Hello,

when I try to build an package mock will fail with:
ERROR: Command(/usr/sbin/groupadd -g 102 mockbuild) failed. See logs for 
output.
At the root.log:
2008-01-18 09:48:01,860 - DEBUG trace_decorator.py, Line: 20:  ENTER: 
doChroot((<mock.backend.Root object at 0xb7dc8e8c>, '/usr/sbin/grou
padd -g 102 mockbuild', ''), {})
2008-01-18 09:48:01,861 - DEBUG trace_decorator.py, Line: 20:  ENTER: 
do(('/usr/sbin/groupadd -g 102 mockbuild', '/var/lib/mock/fedora-de
velopment-i386/root', 0, True, 0, None, None, None, None), {})
2008-01-18 09:48:01,862 - DEBUG util.py, Line: 212:  Run cmd: 
/usr/sbin/groupadd -g 102 mockbuild
2008-01-18 09:48:01,862 - DEBUG util.py, Line: 218:  Executing 
timeout(0): /usr/sbin/groupadd -g 102 mockbuild
2008-01-18 09:48:01,866 - DEBUG trace_decorator.py, Line: 20:  ENTER: 
condPersonality((None,), {})
2008-01-18 09:48:01,869 - DEBUG trace_decorator.py, Line: 30:  LEAVE 
condPersonality --> None

2008-01-18 09:48:01,870 - DEBUG trace_decorator.py, Line: 20:  ENTER: 
condChroot(('/var/lib/mock/fedora-development-i386/root', None), {}
)
2008-01-18 09:48:01,871 - DEBUG trace_decorator.py, Line: 30:  LEAVE 
condChroot --> None

2008-01-18 03:48:01,872 - DEBUG trace_decorator.py, Line: 20:  ENTER: 
condDropPrivs((None, None, None), {})
2008-01-18 03:48:01,873 - DEBUG trace_decorator.py, Line: 30:  LEAVE 
condDropPrivs --> None

2008-01-18 09:48:01,973 - DEBUG util.py, Line: 234:  groupadd: name 
mockbuild is not unique
2008-01-18 09:48:01,977 - DEBUG trace_decorator.py, Line: 27: 
EXCEPTION: Command(/usr/sbin/groupadd -g 102 mockbuild) failed. See logs f
or output.

Any ideas, what goes wrong??

Frank