Hm, I don’t know where all this problems come from. Anyway, I would suggest to try a Win 32bit version, just because QucsStudio is a 32bit one.
The UTf-8 warnings maybe come from special characters (German “Umlaute”)? I think for the first test, the most simple example is the best choice:
x=0:0.1:6;
y=sin(x);
plot(x,y)
