பயர்பாக்ஸ் ஆதரவு மன்றம்

After installing Thunderbird i had first download problems for new Firefox Versions. I tested around, installed everything new and found the solution. Somehow the Maintenance Service didn`t work properly on my machine and after deinstalling and restarting i can update firefox again. Problem remains: When trying to install Offline Languages , see picture, i get the message that it does not work. I tried everything possible, including reinstalling and deleting all old profiles (was a lot of work). Any ideas?