I make a simple test because I don't know if GLBasic fails for Ubuntu and the newer versions or it's problem of GLbasic in self.
Ok, I found in my hard drive the 7 version (a lot of time here !!!

) and I compile a simple Code... really runs perfectly.
I leave you a Image... only print p letter.
In fact I don't have to use with the terminal, only press the Icon and runs perfectly.
Perhaps looking diferences between the 7 and the last Gernnot have more easy correct the little problem.