[FFmpeg-user] Unknown encoder 'libvo_aacenc'

[RITESH MEHANDIRATTA]

i installed ffmpeg on my ubuntu 12.04 .using this link
https://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide .i run the
command


ffmpeg -re -i "sample.mp4"  -vcodec libx264  -vb 150000 -g 60 -vprofile
baseline -level 2.1 -acodec aac -ab 64000 -ar 48000 -ac 2 -vbsf
h264_mp4toannexb -strict experimental -f rtp rtp://127.0.0.1:10000 -flags
+global_header -c:a libvo-aacenc -vn -map 0:1 -f rtp rtp://127.0.0.1:10002 >
10000.sdp


i am getting response it as


 built on Jun  3 2013 23:34:11 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
  configuration: --extra-libs=-ldl --enable-gpl --enable-libass
--enable-libfdk-aac --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libspeex --enable-libtheora
--enable-libvorbis --enable-libopus --enable-libvpx --enable-x11grab
--enable-libfaac --enable-libx264 --enable-nonfree --enable-version3
  libavutil      52. 34.100 / 52. 34.100
  libavcodec     55. 15.100 / 55. 15.100
  libavformat    55.  8.102 / 55.  8.102
  libavdevice    55.  2.100 / 55.  2.100
  libavfilter     3. 74.101 /  3. 74.101
  libswscale      2.  3.100 /  2.  3.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample.mp4':
  Metadata:
    major_brand     : qt
    minor_version   : 512
    compatible_brands: qt
    creation_time   : 1970-01-01 00:00:00
    encoder         : Lavf52.73.0
  Duration: 00:09:56.46, start: 0.000000, bitrate: 524 kb/s
    Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p, 424x240, 420 kb/s, 24 fps, 24 tbr, 24 tbn, 48 tbc
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : DataHandler
    Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo,
fltp, 99 kb/s
    Metadata:
      creation_time   : 1970-01-01 00:00:00
      handler_name    : DataHandler
Unknown encoder 'libvo-aacenc'


how to get-rid of error Unknown encoder 'libvo-aacenc' please someone help!!