I have tried to set up Firebase to work on Xcode using both the quick setup instructions and the manual alternate instructions on Firebase website.
When I used CocoaPods and followed the instructions on the quick setup page, I was able to import Firebase, but I was not able to reference Firebase inside the class. I got the error: Cannot call value of non-function type 'module' xcode
When I tried to set it up manually, I was not able to import or reference Fire base and I got the error: No such module 'Firebase'
I had the same issue when updating my project to the new version of Firebase. A TON of changes were announced at Google I/O and thus there is a good amount of updating to be done.
It sounds like you might be using the old version of Firebase with the new SDK. You should do everything with Firebase 3.0. Hence
var rootRef = Firebase(url:"https://<YOUR-FIREBASE-APP>.firebaseio.com") will now be
var rootRef = FIRDatabase.database().reference().
Take a look at the setup guide at: https://firebase.google.com/docs/ios/setup#prerequisites (be sure you aren't looking at the legacy docs!). If you want to convert code from the old version of Firebase to 3.0, check out the Upgrading tutorial: https://firebase.google.com/support/guides/firebase-ios#get_a_database_reference_numbered