[fixed] 'Graph' sketch froze Arduino, can't upload

Well, I managed to semi-brick my Arduino Uno. Hopefully someone can help me out.

The story:

I've messing around with the Arduino Uno and the sketchpad software for a few days. Everything worked perfectly. Today I decided to connect a temperature sensor to the board. I looked in the example sketches for something I could work off. I decided to upload the 'Graph' sketch (code here). I did this without anything connected to the Arduino except the USB cable. The description for the code is "A simple example of communication from the Arduino board to the computer: the value of analog input 0 is sent out the serial port. Bytes are sent one after another (serially) from the Arduino to the computer."

The code was uploaded successfully but I noticed that the software started responding very slowly. I tried uploading another sketch, but I was not able to.

Here's the error:

Binary sketch size: 450 bytes (of a 32256 byte maximum)
processing.app.SerialException: Serial port '/dev/ttyACM0' not found.  Did you select the right one from the Tools > Serial Port menu?

I did select the right (and only) serial port available from the menu. The tx light on the Arduino is constantly lit, I can only assume that it's bombarding the computer with data and is unable to accept any new uploads. This is corroborated by this screenshot of the serial monitor:

This is a still screencap, in reality the monitor keeps scrolling through similar data very quickly, indicating that a lot of data is being sent through the USB port to the computer.

I have tried pressing the reset button and then immediately trying to upload the 'bare minimum' and 'blink' sketches, but I still get the 'serial port not found' error. I have tried using a different USB port to no avail.

I'm using the Arduino Uno with sketchpad version 021 on Ubuntu 10.04 (Lucid Lynx).

Anyone have any ideas?

Ahhh, I did it! I spent 30 minutes writing that post and making sure I didn't miss anything. After I posted I decided to try upload the bare minimum sketch again. I hit the reset button right after I hit upload (while the sketch was compiling) and it went through fine.

[sigh of relief]