JMTL

I wonder if having too many themes across different platforms has anything to do with it. My main theme is Unified, I have Coverbox for a couple of systems, and Colorful - Dark for another. If I try to go to Colorful - Dark system, then a Coverbox system, that error pops up. Same thing if I load the systems in the other order. Yet, if I revert Colorful - Dark to Coverbox, no error occurs when I switch among those systems.