I've just plugged my Alesis DM6 electric kit into my Mac and tried to run it on Logic Pro 9 using one of the built-in VST kits.

At first it works fine but then it cuts out after about 10 seconds. The cable works fine and if I use my MIDI keyboard it plays the VST instrument fine.

Here is an example of what I mean: http://soundcloud.com/crimson267/example

Can someone help me out with this please?