Not able to upload to Arduino though USB?

After a brake from my Aduino, iv come back it work on a project and am unable to upload a sketch.

keep getting

Serial port 'dev/tt.y.Brook-DataTransfer-1' already in use. try quiting any program that may be using it  

got nothing else plugged into my usb and am using a Macbook OS X 10.5.7

seems to be a solution here

Re: Serial Port Already in Use - MacOSX leopard
Reply #2 - 19.05.2008 at 04:32:57
Also, do you have rxtx.jar or comm.jar or similar in your Java extensions folder? It might interfere with the one that comes with Arduino.

BUT…found my Java extensions folder and there is nothing in it :-/