Upload problem Duemilanove Macosx

I tried to upload the Blink example but there is an error:

I’ve try some other compatible software on my computer.
File> sketchbook> and then there is nothing

So I’ve try in the active screen
Open> select the software> but the button open will not work

Can some one tell which ‘mistake’ I’ve make?

Macosx 10.6.2
Arduino Duemilanove
The Duemilanove is connect to a breadboard with the Nodo project
(sorry for my English)

Did you drag the Arduino.app out of the disk image (and into, say, your Applications folder)?

Thank you for the answer.
Yes I dropped the Arduino.app in the Applications folder