Have you noticed that audacity installed from opensuse or Packman repositories crashes when trying to invoke equalizer?
gdb reports segmentation fault in some sort of GUI function. Same says audacity’s wiki, referring to a known bug in widget utilities. However, audacity’s wiki speaks about hundreds of bugs, and I am not sure what reasons they bring.
Solution found: use audacity version 2.0.2-3.1.2.x86_64 from opensuse 12.3. Seems to work until now.
Audacity was a good, popular program. This is the first time I have a major problem with it.
I hadn’t until you pointed it out, it is the same on my computer (OS 13.1). I tested Audacity with various LADSPA EQs and they do work though, and so do the other effect modules I briefly skimmed through.
Just did a test on my 13.1 system using Audacity 2.0.4, I could not produce the same error when exporting to m4a with ffmpeg as you did. I did not test very thoroughly though, but four successive exports went thorugh just fine. Might be somnething else than Audacity causing the error.