Can't open Bash Shell with postgres user account

This is a new one:

I've got cygwin/postgresql installed on a Spanish Win2K server platform.
All is running fine except if I try to open cygwin with the postgres user
account. All I get is this message:

*** CreateFileMapping, Win32 error 161. Terminating.

I can log on with any other account. I've found absolutely nothing related
to this, and I can't figure it out...something to do with bad permissions or
path info? I incorrectly created the postgres user account the first time,
when I forgot to substitute the password in the following command, and
accidentally ran the mkpasswd command as follows:

net user postgres $password /add /fullname:postgres
/comment:'PostgreSQL user account' /homedir:"$(cygpath -w /home/postgres)"

mkpasswd -l -u postgres >>/etc/passwd

I'm thinking there's some problem related to that mistake...how can I
reverse anything I did related to the postgres account without fully
reinstalling Cygwin/PosgreSQL?

Thanks
Mike