This might be related to a changing hostname -- I meant to post about
this earlier. 

I have a laptop with a wireless card.  I'm assigned different
hostnames depending on location, and it can change when renewing the
lease.  I found that many X apps would
fail as my hostname didn't match the hostname placed in my
.Xauthority.

The solution was to configure /etc/dhclient.conf to supercede my hostname
with something regular:

    supersede host-name "slab";

`slab' is the regular hostname.

-- 
     Brian de Alwis | Graduate student | Software Practices Lab | UBC
"Passivity & cynicism have always come easily to the educated." - Ed Broadbent