as you know not what the problem is nothing would seem out of the question
Well, as he stated.. he's only using 1 servo, lol... so it IS out of the question.
@Sciguy,
I'm not sure if this will solve your problem, but maybe try something like:
if(Serial.available() == 2)
You might be receiving when there is only 1 byte, so it's not giving you the 2nd. Even using > 1 might do it for you.
I'm not too familiar with Processing, so what exactly is being sent back to the Arduino?