Internal Dataflow Error

[aft]

Hi,

I'm Trying a simple pipeline which is not working :

arif at dev:~/GS_samples/sample_media$gst-launch-0.10 filesrc
location="M1F1-Alaw-AFsp.wav" ! alawdec ! autoaudiosink
--gst-debug-level=2
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
0:00:00.045539000  1680    0x1008e10f0 WARN                 alawdec
alaw-decode.c:307:gst_alaw_dec_chain:<alawdec0> no input format set:
not-negotiated
0:00:00.045595000  1680    0x1008e10f0 WARN                 basesrc
gstbasesrc.c:2633:gst_base_src_loop:<filesrc0> error: Internal data
flow error.
0:00:00.045609000  1680    0x1008e10f0 WARN                 basesrc
gstbasesrc.c:2633:gst_base_src_loop:<filesrc0> error: streaming task
paused, reason not-negotiated (-4)
ERROR: from element /GstPipeline:pipeline0/GstFileSrc:filesrc0:
Internal data flow error.
Additional debug info:
gstbasesrc.c(2633): gst_base_src_loop ():
/GstPipeline:pipeline0/GstFileSrc:filesrc0:
streaming task paused, reason not-negotiated (-4)
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...

What i'm doing wrong? I want to understand it conceptually.

-- 
-Cheers
-Arif