Dear Lacot,
I am sorry about that.
You don’t need to re-install OM. Wht you need to do is to delete OM main preferences from here:
/home/youraccount/.local/share/OpenMusic/7.1/OMPrefs.lisp
This should do it.
However, it is strange that you failed to load OMAI lib. I will investigate this and report to its author.
Please do report back.
Best
K