ALSA:Can't subscribe to MIDI port (65:0)

I was wondering if someone could tell me why I get the above message every time I load dosbox? I'm confident that I got all the dependencies right when I first compiled it so I'm a bit stumped.

It's probably something simple like it referring to a midi port I simply don't have but I'd just like someone to confirm it for me one way or another.

Cheers