If you are faced with this problem; ask yourself two questions
- Have you used more than 1 Apple ID with the same Apple Device during its lifetime?
- Have you synchronized your iPhone with PC’s running different Apple ID’s?
If either of them are true the real reason for the error is because the version of the App that you wish to update was installed / updated / synchronized using an alternate or old Apple ID
To resolve this issue; just delete the App. When re-installing the App again from iTunes, it will automatically download and install using the current configured Apple ID on your device