Hello,
Today, as everyday, I wanted to continue my work on my app so I loaded my project, connected MIT app inventor with my phone via USB and then... error 
Here below is the error after I created fully new blank project, connected via USB, added label (no error), added ClickZ extension (only as example) and error appears:
When I use ANY OTHER extension this error appears again with extension name in red square.
So here are conditions when this error appears:
- MIT app companion 2.62u and 2.63u version used (didn't checked other)
- Project is started in emulator or phone via USB
- Already started project or even completely new blank project
- ANY extension added to components (after importing = no error, after dropped to project = error)
- even tried with new mit app inventor account =same situation, error
So everything is OK as long as I use built-in components like button, label and so on.
I tried clearing cache and data files of MIT app companion = no effect
Everything was working fine until today. Nothing changed in my PC or my phone. Even if so, creating new project or reinstalling companion app should help - but it didn't.
For me it looks like major MIT app environment bug, but as I read community it looks like this problem is not met by other users so I don't know.
Any ideas how to work this out? 