Can't Upload to my arduino Nano v3

Hi everybody,

I’ve hot an arduino uno and it work perfectly, but now i’ve got an arduino nano V3 i when i’m trying to upload a program on it there is this error message:

"
avrdude: stk500_recv(): programmer is not responding
processing.app.debug.RunnerException
at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:129)
at processing.app.Sketch.upload(Sketch.java:1692)
at processing.app.Sketch.exportApplet(Sketch.java:1605)
at processing.app.Sketch.exportApplet(Sketch.java:1577)
at processing.app.Editor$DefaultExportHandler.run(Editor.java:2397)
at java.lang.Thread.run(Thread.java:680)
Caused by: processing.app.debug.RunnerException: Problème de téléversement vers la carte. Voir http://www.arduino.cc/en/Guide/Troubleshooting#upload pour suggestions.
at cc.arduino.packages.Uploader.executeUploadCommand(Uploader.java:113)
at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:127)
… 5 more
"

i’m working on mac.

pleaeeese help ;e

Capture d’écran 2013-09-26 à 21.00.20.png