iOS developer profile provisioning
If an existing profile and its any related certificates are expired, then look at https://developer.apple.com/library/ios/#documentation/IDEs/Conceptual/AppDistributionGuide/Troubleshooting/Troubleshooting.html#//apple_ref/doc/uid/TP40012582-CH5-SW1 first. If this still does not help and you want to restart from the clean (i.e. you did not publish any Apps before), then simply clean certificates from your Keychain (named iOS blah) and next visit https://developer.apple.com/account/ios/profile and clean everything (certificates and profiles, not identifieris and devices) and recreate provisioning profiles from the web page (not from Xcode). It will ask you to upload the development certificate from your Mac (which you can generate following instruactions at http://developer.apple.com/library/ios/#documentation/ToolsLanguages/Conceptual/YourFirstAppStoreSubmission/ProvisionYourDevicesforDevelopment/ProvisionYourDevicesforDevelopment.html). Follow the instruction to download certificates and profiles. At the end restart Xcode and also refresh from the Organizer.