I can't say for sure that I know what the problem is, but I've got an idea. I think you should play the entire range of the keyboard. There may be only 4 or 5 keys that do anything. I was concerned about this with my bass/drums board. Some of the patches on it are devoted exclusively to snare. So, they used only about 4 keys in the entire patch. My guess is that you got lucky enough to hit those keys a couple times, but the rest of the keys would do nothing regardless how much pounding you did.
The way to fix this, should you do so and if this is the problem, is to adjust the key range for each tone. If that doesn't work, then the patch is using a multi-sample sound that doesn't cover the entire range. For instance, my drums and bass board has a patch that handles both a closed and open hihat in a single tone.
[This message has been edited by FAEbGBD (edited 03-17-2002).]