ArrayIndexOutOfBoundsException error in code

Hi!

I'm trying to visually show a heartbeat with processing, the code that detects the heartbeat is from Arduino (downloaded from pulsesensor.com, who make the sensor). The manufacturer also provides a processing code, but I get the following error when I try to run it:

ArrayIndexOutOfBoundsException: 9 in the following line of code:

port = new Serial(this, Serial.list()[9], 115200); // make sure Arduino is talking serial at this baud rate

I'm very new to processing (and Arduino), but to me it seems like it doesn't like the [9]. However, I have no idea what to change it to. What should I replace the 9 for (or what is wrong with the line) to make it work?

Thanks!