Problem starting monitor

I have edited /etc/monitorcap but can still not manage to
open a monitor with d.mon start=x0. When I try I get these
error messages:

GRASS-GRID > d.mon start=x0
Graphics driver [x0] started
Graph_Set: can't open
Please start graphics monitor <x0>.
Error - Graphics monitor <x0> not running!
Problem selecting x0. Will try once more
Please start graphics monitor <x0>.
Error - Graphics monitor <x0> not running!

Can anybody help me?

Jan.

----- End Included Message -----

Dear Sir:
For some reasons, your graphics monitor might be locked.
Try running "d.mon unlock=x0", then "d.mon start=x0".
Good luck to you.

Sincerely,

John Wu