FFmpeg AMV Encoding Failure

D:\Users\User\Music\ConversionTests>ffmpeg -i sample.wmv -s 176x128 -r 16 -ac 1 -ar 22050 -qmin 3 -qmax -3 sample
.amv
ffmpeg version 0.9, Copyright (c) 2000-2011 the FFmpeg developers
  built on Dec 12 2011 12:34:19 with gcc 4.6.1
  configuration: --enable-decoder=aac --enable-decoder=dca --enable-decoder=libopencore_amrwb --enable-decoder=aac_
latm --enable-decoder=dfa --enable-decoder=libopenjpeg --enable-decoder=aasc --enable-decoder=dirac --enable-decode
r=libschroedinger --enable-decoder=ac3 --enable-decoder=dnxhd --enable-decoder=libspeex --enable-decoder=adpcm_4xm
--enable-decoder=dpx --enable-decoder=libstagefright_h264 --enable-decoder=adpcm_adx --enable-decoder=dsicinaudio -
-enable-decoder=libutvideo --enable-decoder=adpcm_ct --enable-decoder=dsicinvideo --enable-decoder=libvpx --enable-
decoder=adpcm_ea --enable-decoder=dvbsub --enable-decoder=loco --enable-decoder=adpcm_ea_maxis_xa --enable-decoder=
dvdsub --enable-decoder=mace3 --enable-decoder=adpcm_ea_r1 --enable-decoder=dvvideo --enable-decoder=mace6 --enable
-decoder=adpcm_ea_r2 --enable-decoder=dxa --enable-decoder=mdec --enable-decoder=adpcm_ea_r3 --enable-decoder=dxtor
y --enable-decoder=mimic --enable-decoder=adpcm_ea_xas --enable-decoder=eac3 --enable-decoder=mjpeg --e  libavutil
   51. 32. 0 / 51. 32. 0
  libavcodec   53. 42. 0 / 53. 42. 0
  libavformat  53. 24. 0 / 53. 24. 0
  libavdevice  53.  4. 0 / 53.  4. 0
  libavfilter   2. 53. 0 /  2. 53. 0
  libswscale    2.  1. 0 /  2.  1. 0

Seems stream 1 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 29.97 (30000/1001)
Input #0, asf, from 'sample.wmv':
  Metadata:
    SfOriginalFPS   : 299
    WMFSDKVersion   : 11.0.6001.7000
    WMFSDKNeeded    : 0.0.0.0000
    IsVBR           : 0
    title           : Wildlife in HD
    copyright       : © 2008 Microsoft Corporation
    comment         : Footage: Small World Productions, Inc; Tourism New Zealand | Producer: Gary F. Spradling | Mu
sic: Steve Ball
  Duration: 00:00:30.09, start: 0.000000, bitrate: 6977 kb/s
    Stream #0:0(eng): Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, 2 channels, s16, 192 kb/s
    Stream #0:1(eng): Video: vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 1280x720, 5942 kb/s, 29.97 tbr, 1k tbn, 1
k tbc
[NULL @ 032570e0] Unable to find a suitable output format for 'sample.amv'
sample.amv: Invalid argument