When you use spell IMAGINATOR for the first time NPC, that appears and with whom you can engage a dialogue to change settings, can disappear. if it happened - save game after using the first time IMAGINATOR spell, and after NPC disappearance, then load this save. After "save - load" the dialog with IMAGINATOR NPC always will work properly. This is a bug in IMAGINATOR mod that developers have not been able to fix, but provided the solution which I have described above.