SimpleMessageSystem interrupt PWM?


I have problem with MAX/MSP - SMS and arduino. I use arduino 6 PWM outputs to drive brightnes of row of 8leds. (each PWM drives 8 leds)

Always when I am sending data from MAX/MSP through SimpleMessageSystem library the leds stop shining for I while. It looks like the data transfer always interrupt the PWM output for a short moment. It makes led blinking, when I am changing brightness values.(and I am changing it almost always by the different functions...) But I want it smooth....

I dont know how works the SimpleMessageSystem library, but for sure there are some functions. I run 9600baud, but the speed change doesnt solve the problem. Does, interrupt the PWM output?

Please does anyone have any idea how to improve it? Thanks a lot :)

...really noone has this experience? Please did anyone notice the same interruption on PWM ( or maybe on whole ATMEGA 168) when the data from MAX/MSP is being transfered? I think it is very important thing.... Thanks for any idea whats going on :)