Issues with gstreamer when trying to stream audio and video from a Raspberry Pi

I am currently trying to stream both audio and video live data from a Raspberry Pi to a client using GStreamer.

raspivid -t 0 -w 1280 -h 720 -fps 25 -b 1500000 -o - | gst-launch-1.0 -v fdsrc ! h264parse ! muxout. alsasrc device=plughw:1 ! queue ! audioconvert ! lamemp3enc ! muxout. matroskamux name=muxout streamable=true ! gdppay ! tcpserversink host=192.168.0.49 port=5000

The video part comes from a RPi camera module and the audio is from a microphone connected to a USB sound adapter.

Unfortunatly, I only get this error:

ERROR: from element /GstPipeline:pipeline0/GstFdSrc:fdsrc0: Internal data flow error. Additional debug info: gstbasesrc.c(2865): gst_base_src_loop (): /GstPipeline:pipeline0/GstFdSrc:fdsrc0: streaming task paused, reason not-negotiated (-4)

I don't have any clue what it is talking about. Thank you very much for your help.