ffmpeg thumbnail problem

I have installed FFmpeg and videos are converted like it should be, but the problem is when I want to create a thumbnail I get always something as this: View picture - pic.filehostserver.eu

When I use mplayer I get this:
Error opening/initializing the selected video_out (-vo) device.

With this command: mplayer /home/vid.avi -ss 1 -nosound -vo jpeg:outdir=thumbs -frames 3

The command mplayer -vo help returns this:
MPlayer SVN-r29543-4.1.2 (C) 2000-2009 MPlayer Team
Available video output drivers:
fbdev Framebuffer Device
fbdev2 Framebuffer Device
cvidix console VIDIX
null Null video output
mpegpes MPEG-PES to DVB card
yuv4mpeg yuv4mpeg output for mjpegtools
tga Targa output
pnm PPM/PGM/PGMYUV file
md5sum md5sum of each frame


So the Jpeg is not installed, but how can I install this? Or how can I make it work to create thumbnails with ffmpeg?

Install gd library before installing mplayer. Both ffmpeg and mplayer need GD to create thumbnails.

I already checked if it was installed when I had the problem and it was. The strange thing is that it has worked untill I tried to install it again with yum (RPM forge)

How can I solve this problem?

Install from yum is very old, may not work. Install from source.

I will give it a try, before I had installed the yum version I had an other version compiled which did work.

okay, I have re-installed ffmpeg by myself and a lot of other codecs and it works now. Thank you for your help!