[volkadav]

Just a note that you aren't alone. Same symptoms, same machine, same irix version. Changing the new user's shell to /sbin/csh lets me log in, but the window manager doesn't start (plain 'x' cursor). su works then too for a shell. Amusingly (?) the green flash and return to login phenomena also happens with the guest/demos accounts that were there from the beginning. I probably won't have time to fool with it more until the weekend but will update here if I find a solution.