I remember having a wiring problem when trying to run midi.
In the example from http://itp.nyu.edu/physcomp/Labs/MIDIOutput
, they use a female midi adaptor. I used a male midi adaptor, so all the pins were mirror images. I had to invert the 5v and the TX connections to make it work.
Also, perhaps you could use a USB interface for your midi. On mine, every time I send a valid signal, there's a led that blinks to show activity, which helps on debugging. Also, the usb port is easier to use with midi tracking programs.