I came across this problem with the IroIro plugin (aka, the great Bizz's Utau Plugins), where a message would pop up in full-on Japanese. To those who can't read it, all that is recognizable is "oto.ini", "OK", and "Cancel".
Essentially, the pop-up is saying that there was an issue reading the oto.ini, and where the problem lies. You can either fix it by pressing OK, or ignore it by pressing Cancel.
This is how to fix it.