[plug] Weirdo X, GDM behaviour with no active server

[Tim White]

I have too machines running GDM without a local server so that they can 
respond to XDMCP requests.
Both are gdm=2.2.5.5-2 and gdm is running with out any local servers.
They both randomly 'drop out' and don't answer XDMCP requests.
e.g. They appear in the gdmchooser and then hitting refresh they 
disappear. This happens to both computers from a number of gdmchoosers. 
At one time one of the servers appeared but had the text 'server busy' 
underneath it.
Any ideas? I can't see anything in the logs.
Tim