Playing midi?

[Bruno Buys <bruno.grupos@gmail.com>]

This is debian sarge with marillat multimedia sources. I'm trying to 
play a midi file, but I get a "Could not open /dev/sequencer to get some 
info. Probably there's another program using it" error, from kmid. 
That's the first time I try to open a midi file, so, probably I lack 
some config. Trying to open Settings > MIDI setup brings me the same window.

What can I do?

thanks!