the DWORD is representing a short MIDI Event message.
Normal MIDI Events can be up to 4 bytes: status byte, data1, data2, data3
this is how i understand it anyway.
the control change and channel information is in the first byte (status byte), the value of that is in the second byte(data1). in this message, the third and forth bytes are not used.
http://harmony-central.com/MIDI/Doc/table1.html
That is sorta what is going on here. It's not a great example, but you might get a more clear picture of the MIDI event.