Otmar Schaal - 2012-07-17

I am running eXe-learningplus. There is the following problem.
I want to import a GeoGebra App. I did all the steps described in the manual.
The dynamic GeoGebra-Site is not shown after finished (green hook).
But I always get an error-box:

Illegal Operation in Plug-in:
Text: The plugin performed an illegal operation. You are strongly advised to restart Firefox.

This Message repeats at any changes or even other inserts.
I use Firefox13, the newest Java and the newest GeoGebra 4.

I would be very thankfull for help.

Otmar Schaal