Right, seems that the problem lies in the fact that the users group's gid on SuSE is less than GID_MIN as defined in login.defs, which means that it's not in the range that's available bu default in GST::Users. If you enable the 'view all users and groups' checkbox, then it's used as the default, but that doesn't cut it. So, I' going to have to rig it so that under SuSE, GST::Users uses SYSTEM_GID_MIN.