Arduino Occupying Serial Port

It seems a program I uploaded to it to constantly print an analog value from a pin is hogging the serial connection, and I can't upload a new program. "avrdude: stk500_recv(): programmer is not responding" I am on Ubuntu 10.04, and it was working before I made that mistake. Any help would be greatly appreciated.

Did you try pushing the reset button while uploading the sketch?

More precise info is useful - which Arduino, which OS version did it work on?

I have the same problem with my board.. Ubuntu mav 10.10 and it is a Uno board. The tx led is always lit and it does reset with button but straight away on comes tx. and console as orig post..

Basically exactly the same as andrewsut. Now under Win7 and the TX light is off, but I still can’t upload.
Its an Uno.