[HELP] Could not load controller module

I try to duplicate a new category module but i get this error

Error: Could not load controller module/category2!

Anyone can help me?

Thanks very much

Well there is a guide for duplicating modules. But I also already have a mod that adds 3 duplicated category sideboxes (for a total of 4), complete with instance selector here. So you can set different categories to different instances of the sidebox