MOTU MX4 in rtas.

[baboon]

I have a problem using mx4 in protools le(7.4).
It is that the mx4 works fine,however when i hit a key from my controller(i have two),you hear the sound 2 seconds and then nothing,so it is for every sound i choose.
Are there some,with a mx4 in protools?And it is the last update,also for intel.

Imac 2.16 GHz,intel core 2 duo,2 GB ram,version 10.4.11(tiger)