GP Premium - Can´t edit page content

Hi,
i have purchased GP Premium and i was using it without problem until now.
But today i recognized, that i can´t edit content of any page in administration. Although the page is not empty, it seems to be empty and i am not able even to click into the area of page. If i switch to HTML, everything is ok, but Editor is not working (please see this printscreen)

I´ve tried to disable all my installed plugins and the problem is really in GP Premium plugin. With GP Premium deactivated, everything is working fine.

I´ve tried it on Google Chrome and IE and the problem is same.

Do you have some idea where the problem could be?
I have GP Premium 1.2.3. Is there some newer version?

Thank you very much in advance
Best regards
Martin