i can´t write sth in the "Actor at the top or do you say the main actor of the walter class ?"
because if i cklick on Actor there is only :
Open Documantation and new subclass...
I think it would be best for you to comment out the problem lines, compile the project, and upload it here. Make sure you check the 'Publish source code' checkbox.
If you project compiles you can use the 'Share' button (near top-right of window) to upload it on this site. Use the 'Publish' tab (along the top of the new 'Share' window) and be sure to check the 'Publish source code' checkbox before clicking on the 'Share' button in the 'Share' window.