Im getting a similar error when a user is trying to join a project. The project already has 4 members and for some reason another user is generating the following error: *** WARNING: Could not find an unused unix_uid! *** /usr/testbed/sbin/newuser: Could not create new user!
This typically happens if you have added (or deleted) an account by hand to the password file on boss, since that will mess up what Emulab thinks is supposed to be there. Yes, it does seem a bit fragile ... sorry. Anyway, what is the last entry in the password file? Lbs