Trophy data is incorrect or may have been corrupted.
Restart the game to automatically reinstall trophy data.
If the problem persists, delete the PS3 system user profile that is associated with your Sony Entertainment Network account by going to Users and highlighting the user you want to delete. Press the Triangle button and select [Delete] to delete the user. Please note that there is no need to delete your Sony Entertainment Network account.
Create a new PS3 system user profile by going to Users > [Create New User] on the XMB™ Menu.
Sign in to PlayStation Network from the new user profile.