Okay, that explains that mystery haha however, I may be missing something, since the USI launchpad doesn't have an option to show the UI, nor does the Toolbar addon. Not sure if this is an issue with EPL or the other mods though
EDIT: Just found a thread with the same issue. Totally forgot I was using the 64-bit workaround which was what was causing the problem for the other user. Well, damn, guess I can't launch ships from Minmus until 1.1