i did some tests.
if i make a new project, and i add ValerypopoffJS plugin, minify work.
then i added some ValerypopoffJS events and actions, minify work.
then i insert a new object, sprite, and i get the error.
i tryed to add ValerypopoffJS plugin in 4-5 full projects and i get the error.
i tryed to uglify c2runtime.js (online) and its work.
I used c2 release 269 and 277 (64 bits).
How to get the error.
1. open a c2 project. (no new or emptyone)
2. add the ValerypopoffJS plugin.
3. export as html 5 website.
4. set enable the minifi option.