pure data+ardunio

Hello, I am a first timer in arduino. I want to connect two piezoelectric mics into it and control a Pure data patch with its response.
Every time I download the firmware needed to connect both softwares and the board, i try to compile it in arduino and always shows an error in printing some kind of variable not specified… i am not very good with C++.
Also, I see that i have to find out the COM port comunicating the soft with the board. How di I see this?
I work in MAC OS X 10.6.3 version.
Thanks a lot.

If you could post your source code, and the error message I could at least give it a try...

Ney, after messing around I was able to make a connection with pure data succesfully. I was wondering. My intentions are to simply control a bang in pure data, controlled by a piezo device through arduino. Could you give me a hand with info in the arduino .pde file?

Look for "Arduino knock sensor" (the forum doesn't allow me to post links because it is my first post :)