I found out myself: The blank spaces before each comment # have been interpreted and displayed in the skin. If you write each comment right after the command without any blank spaces following the command the skin is displayed all right!

Like that:
#####Current Track Title#####
%Vl(a,5,184,310,16,5)%Vf(00b000)%Vb(000000)# viewport
%s%ac%?it<%it|%fn># format
Not like this:
#####Current Track Title#####
%Vl(a,5,184,310,16,5)%Vf(00b000)%Vb(000000) # viewport
%s%ac%?it<%it|%fn> # format