"Cannot Find/ Load this file. Check your Audio Preferences"

Getting an error on a working VST I made when it's run in a DAW. Error is:


"Cannot Find/ Load this file. Check your Audio Preferences MIDI path setting:" 



If I click "OK", the error window goes away, and I can use the VST. 

Sometimes two of them pop up, and I have to dismiss both of them. 

Happens also on other people's computers. VST more or less works otherwise. 

Here's the addition that made this happen: 



It's a module for adding MTS microtonal tuning files. The microtonal function works. 
Any help would be very appreciated. 

thank you!