Hello,
I have found a bug in Sketchup license system. Problem is with my user name “Paweł K.”, especially with Polish letter “ł”. I had a lot of problems with lost extensions licenses and I have found that EW.lic file has more than 1GB (also because of that Sketchup was starting in more than minute ;/).
I deleted it and uninstall all paid extensions. Then I started to install them once again. Everything was working. But after installing second that first stopped to work (no license).
And in .lic file I have found something like that:
LICENSE trmbldg…
… customer=“Paweł K.”…
LICENSE trmbldg …
… customer=“PaweÃÂ
ÃÂ K.” …
LICENSE trmbldg …
… customer=“PaweÃ
 K.” …
LICENSE trmbldg …
… customer=“PaweÅ K.” …
With that file only first extension is working correct. After installing new extensions, licenses of previous in file were “destroyed”. I corrected that letters in file and it’s working now but I don’t know if Sketchup will override it someday.