mplayer help

[Thomas M. Albright]

mplayer works fine for me from the command line, but when I try using 
the GUI version, (gmplayer,) which is part of the mplayer installation, 
I get an error:
     Error opening/initializing the selected video_out (-vo) device.

Any tips of how I can make this work?

Thanks!
  Tom

-- 
TARogue (Linux user number 234357)
 He who would make his own liberty secure must guard even his enemy from
 oppression; for if he violates this duty he establishes a precedent that
 will reach to himself. -Thomas Paine, philosopher and writer (1737-1809)