You must mean a Standard Midi File or SMF. They come in Type 0 and Type 1.
General Midi (GM) is simply an agreement amongst manufacturers that a certain patch number will produce a certain type of sound (over-simplified, but essentially true). You need a General Midi sound module in order to do your arrangements in General Midi format. Do you have one?
PTLE certainly can export an SMF, but you have to assign the patch numbers in the tracks correctly or it won't make any sense to someone using a GM sound module.
Here is a link to some essential General Midi information:
http://www.midi.org/about-midi/gm/gm1sound.shtml