winff ffmpeg: unrecognized option '--ar' Lucid Lynx

following error message appear if i try to convert a mp3 file:

Duration: 00:07:40.04, start: 0.000000, bitrate: 187 kb/s
Stream #0.0: Audio: mp3, 44100 Hz, stereo, s16, 192 kb/s
/usr/bin/ffmpeg: unrecognized option '--ar'

please help