Fwurm,
I can sympathize with your problem. I had a problem with root on an HP box a few months ago.
What I did was shutdown and come back up to single user mode.
When the system is coming back up, it should have a moment where it will ask you if you want to interupt. Do it.
This should take you to single user mode. You should be able to mount all available filesystems with "mount -a" command.
then do "df -k" to see if you can see all disks. Somewhere under /etc you should either have a backup password file you created or there should be a default minimal password file with just root, daemon, bin and some other ids in it.
You should save your current bad passwd file and copy over the minimal passwd file. This should help you get back upto multi user mode.
Hope this helps. Of course my advice is based on HPUX, so your results may vary.