Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

[Rocky]

I am trying to convert an avi video file to flv format via FFMPEG with the following command:

    -i C:\files\input\test.avi -y -ab 448k -ar 48000 -vcodec mpeg4 -s 640x480 -f flv C:\files\output\test.flv

Here is the response I am getting from ffmpeg:

Input:

    Input #0, avi, from 'C:\files\input\test.avi':
      Metadata:
        encoder         : VirtualDubMod 1.5.10.2 (build 2540/release)
      Duration: 00:01:00.00, start: 0.000000, bitrate: 1813 kb/s
        Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (XVID / 0x44495658), yuv420p, 640x272 [SAR 1:1 DAR 40:17], 25 tbr, 25 tbn, 25 tbc
        Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, 5.1(side), s16, 448 kb/s

Output:

    Output #0, flv, to 'C:\files\output\test.flv':
      Metadata:
        encoder         : VirtualDubMod 1.5.10.2 (build 2540/release)
        Stream #0:0: Video: mpeg4, yuv420p, 640x480 [SAR 30:17 DAR 40:17], q=2-31, 200 kb/s, 90k tbn, 25 tbc
        Stream #0:1: Audio: mp3, 48000 Hz, 5.1(side), s16, 448 kb/s
    Stream mapping:
      Stream #0:0 -> #0:0 (mpeg4 -> mpeg4)
      Stream #0:1 -> #0:1 (ac3 -> libmp3lame)
    Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

Can you tell me what is MAY BE here? and what is wrong above? I am having the latest dll of FFMPEG

[Carl Eugen Hoyos]

libmp3lame does not support multichannel (5.1) audio.

For future bug reports, please always add complete command line and complete, uncut console output.