Problems using groupshare

I have been sent a file to review and I can't check in the reviewed file .
I get the following message:

The element 'PackageProject' in namespace 'sdl.com/.../2010' has invalid child element 'Users' in namespace 'sdl.com/.../2010'. List of possible elements expected: "LanguageDirections" in namespace ''sdl.com/.../2010'

Thank you