You are currently using the ARC to reference count for you.
(ARC is "Automatic Reference Counting", a new feature to iOS 5).
Therefore you do not need to manually retain or release.
You can either remove your retain call all together or turn off ARC by doing the following:
Click on the name of the project on the navigation view in the left side,
go to Targets -> Build Phases and add -fno-objc-arc to
the "compiler flags" for any relevant files.
