To answer your problem with monitor x0 not being able to lock,
try looking in your ~/grass/locks. When grass is not running
there should be no files in any of those directories (if
single user). You can delete them for a quick fix. Im not
sure what causes this to happen. On my system, running solaris2.2,
the window sometimes crashes and leaves me with the problem you
currently have.
Good Luck.
Kym M. Lenkus
Davidson Laboratory