GIMP execution error for file load procedure

Hello,
Well I’ve never had any problems with Gap on my Windows machine, but I just tried converting this video I made in Blender to a GIF in GIMP using GAP on my Ubuntu 10.04 machine, and I got this error. Any solution for me problem ? How can I solve this please ?
Thank you experts !

GIMP Message
Execution error for procedure ‘gimp-file-load’: Unknown file type.
