createUser overwrites users on local machine

I've had this happen twice to me now and I am wondering what I might do to stop it. Here are the specs: [i]10.5.8 client (not server) build machine (Mac mini Late 2009, server model) Building a 10.5.8 image instadmg.bash r318 latest version of createUser (1.0.3?) no use of InstaUp2Date [/i] I was having some problems with core parts of the OS not installing properly (QuickTime 7, DVD Player) when using the 1.6b2 script and the -s option, so I downloaded the latest script (r318) and tried it (no -s or any other option). Disaster. Late in the build process, I noticed the terminal spitting out pages of "lsof: …UID 501" (sorry I don't have the full line right now). It did eventually finish the build. Using file sharing in the Finder, I tried to access the newly-created disk image by authenticating as the admin user (501). I connected without problem, but I could not view the content of any of my non-public folders. I went back to the host machine and logged out of the admin account. When I was dropped in to the login screen (which uses the default list of users behaviour), the admin user was not in the list. A new user was the only one available in the list, one which corresponds to the second (non-admin) account I create in the build train using another createUser package. Rebooting changed nothing. First question: can anyone remind me of the trick (that I heard at Macworld 2008 IT track) that would let me bring up the user/password dialogue text boxes so that I could try to type in my admin username and password? Two, any suggestions on how to avoid this happening in the future? I have a fairly recent Time Machine backup, so I can rebuild from scratch if need be, but it is a tedious process, especially on a machine that technically is not supported to boot into 10.5.8. Thanks.