I couldn't find anything available for Tapi which means that the program you're using is a different one. However, the best way to track a stolen iPhone 4 is through the iCloud service. This procedure involves that you already configured the phone for Find My Phone and iCloud service is active.
If it is, go to the following website, log-in with your Apple ID and then use the Find My Phone features.
You have more information on the following link: http://www.apple.com/icloud/find-my-iphone.html