If you have existing Planning applicatoins when installing SP1 for PerformancePoint, you must upgrade the databases to reflect the install. Otherwise, you will not be able to see or connect to the applications after installing. Also, you will receive an error in the planning server log:
Failed to load application [Application] due to incompatible versions. Please upgrade the application to version 3.0.3917.0
After installing SP1, to upgrade the existing applications, use Planning configuration manager:
Be sure to check the Upgrade Application Databases box, as it is unchecked by default.
** After this process, you must go into the Planning Admin Console, and "Take Online" each application.