[dvd::rip] subtitle preview not working

[Edmund Mergl <e.mergl@xxxxxxxx>]

Clicking on 'Open' on the subtitles page, opens a black window
which closes immediately.
Entering the command found in the log manually gives an X Error:

 transcode -H 10 -a 0 -x vob,null -i /usr/local/dvdrip/Atanarjuat/vob/001/ -w 
2000,50 -c 9-2734 -L 97907 -A -N 0x2000 -f 25 -Y 0,10,0,4 -B 24,0,8 -R 1 
--print_status 20    -J pv=cache=20 --socket /tmp/tc.4728.114650563256486.sock 
-u 1 -J extsub=0:4:0:0:0

X Error of failed request:  BadAccess (attempt to access private resource 
denied)
  Major opcode of failed request:  140 (XVideo)
  Minor opcode of failed request:  19 ()
  Serial number of failed request:  30
  Current serial number in output stream:  30

This happens on a FC4 system using the Gnome desktop.
Does anyone know how to fix this problem ?

Edmund