Please describe the problem:
In Jokosher, we have a callback that responds to the pad-added signal that hooks
the gnlcomposition to an audioconvert (the audioconvert links to an adder !
level ! alsasink).

The first time we begin playback, it works fine, but when playback is stopped
and started again, this error is displayed:

(Jokosher.py:12740): GStreamer-CRITICAL **: Padname src0 is not unique in
element internal-decodebin, not adding

My assumption is that there is a problem with the dynamic pad on the
composition. The fact that error refers to an internal-decodebin gave me the
impression that this is an internal problem in gnonlin - Jokosher should never
need to concern itself with internal-decodebins.

I have switching GST_DEBUG and created an error log. You can grab this at
http://jonobacon.org/files/jokosher-gnonlinbug-errorlog.gz

To see the Jokosher code, see Project.newPad() for where the pad it added.

Interestingly, this only happens with imported audio. When we record audio, it
works fine.

Steps to reproduce:
1. Grab Jokosher SVN (checked with r294)
2. Create a new project, import some audio and press play - playback works fine.
3. Press play again. Bang! Bug happens.


Actual results:
You see the bug.

Expected results:
Playback should work each time you press Play.

Does this happen every time?
Yes.

Other information: