Error connecting iPhone OS- Help me!

Hi Techyv,
I use Iphone software 3.1.3.My iphone is listed in the Xcode Organizer Window. I received the required keys or certificate (whatever you call). However, when I connect my iPhone to my laptop and choose ‘Build and Go’, received the above error. I tried rebooting the device and the Xcode.
Please help. It was not a cakewalk as I thought.
Error: “Error Starting Executable
No provisioned iPhone OS device is connected.”
Thanks,
Marin
