MIDI Device for SoundFonts

I can't get it play at all. I have Midiyoke showing on the ports. I selected port one as midi ports in SFZ and Composer. On SFZ I pressed file/load programs , and selected my soundbank set of samples. No problem. Select Midiyoke as default device in Composer, it won't even start to play a midifile. It freezes. I change back to GS Wavetable, and it is okay. When I rightclicked on the blank field, and loaded the same bank of samples in SFZ, it says "not enough memory".

I don't know why the file/program loads, and the "blank load doesn't, unless that is for one sample for one track.

Any ideas ?