It was not a bug of this great extension ... I had added a line in the .htacess and it was causing the conflict. I removed this line and everything was Ok ... thank you very much and congratulations for the great work
I have the same problem with the difficulty level option. I have installed the Guru light to test if the extension have the functionality I need (I use Chamilo at the moment). I erased the preinstalled courses and wanted to make my own course from scratch. I cannot create lessons as the difficulty level option is mandatory for creating lessons. It is quite vital for testing your extension.