grass4.1-d.mon-X emulation problem

[ALOBO]

Hi!

I'm using a PC with a program for X emulation to use
an IBM RS6000 remotely. Everything works fine but
grass4.1. 
When I enter d.mon start=x0 I get the following uggly message:

X Error of failed request:  BadAlloc (insufficient resources for operation)
  Major opcode of failed request:  53 (X_CreatePixmap)
  Serial number of failed request:  49
  Current serial number in output stream:  51

It's not a grass error, it's an X error but ... 
any help there?

Agus