Ffmpeg streaming crash about 2 minutes

Hi everybody,

I trying send my cctv camera to Ustream using ffmpeg.
My system is GNU/Linux Opensuse 11.4

In a konsole i write this:
ffmpeg -f v4l2 -s qvga -i /dev/video2 -f alsa -i micro -ac 1 -acodec libmp3lame -ab 32k -ar 11025 -threads 0 -f flv "rtmp://blablabla"

ffmpeg say "alsa @ 0x80787e0] ALSA buffer xrun."
but the stream is sending and i can to see webmcam on ustream.tv

About 2:30 min and the size 28000kB
ffmeg is going down and connection is broken.

If I send the videostream without ALSA sound I get the same result too.

Whereis the problem? The system log is clear.
The terminal dont show any error.

Some lines before the crash.
ffmpeg -f v4l2 -s qvga -i /dev/video2 -f alsa -i micro -ac 1 -acodec libmp3lame -ab 32k -ar 11025 -threads 0 -f flv "rtmp://xxxxxx"
Input #0, video4linux2,v4l2, from '/dev/video2':
Duration: N/A, start: 1335205444.432508, bitrate: 23039 kb/s
Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240, 23039 kb/s, 25 tbr, 1000k tbn, 25 tbc
[alsa @ 0x80787e0] Estimating duration from bitrate, this may be inaccurate
Input #1, alsa, from 'micro':
Duration: N/A, start: 1335205444.448176, bitrate: N/A
Stream #1:0: Audio: pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
[buffer @ 0x8084e20] w:320 h:240 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:
Output #0, flv, to "rtmp://xxxxxx"
Metadata:
encoder : Lavf53.32.100
Stream #0:0: Video: flv1 ([2][0][0][0] / 0x0002), yuv420p, 320x240, q=2-31, 200 kb/s, 1k tbn, 25 tbc
Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 11025 Hz, 1 channels, s16, 32 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo -> flv)
Stream #1:0 -> #0:1 (pcm_s16le -> libmp3lame)
Press [q] to stop, [?] for help
[alsa @ 0x80787e0] ALSA buffer xrun.
^L^Ce= 3819 fps= 25 q=0.0 size= 28621kB time=00:02:31.40 bitrate=1548.6kbits/s


Any suggestion are wellcome