[Orgmode] Error in post-command-hook

[Markus Heller]

Hello,

I'm using org version 6.33f and emacs 23.1.50.1 on Windoze XP.

When I've workd with org mode for a few hours, and invoke the agenda, I 
sometimes get the following error message:

Error in post-command-hook: (buffer-read-only *Org Agenda*)

I haven't been able to track down what triggers the error, it does occur 
after a few hours of work, I just can't reproduce the exact steps.

Any ideas how I could track that down?

Thanks
Markus