I had a problem installing this update ( KB2687455 ) on a Windows 7 (64-bit) laptop. Tried the normal Windows Update method, and tried the offline file - neither would succeed. Finally succeeded in installing the update using the offline file after changing permissions on the following two folders (it is possible only one of the folders needed the permissions changed). For the folders below I gave my user account full control.
For these two folders I have the following four user names listed: Everyone, SYSTEM, Administrators (GomJabbar-THINK\Administrators), and Users (GomJabbar-THINK\Users). It was this last one that needed full control. Not sure why my account is listed as both an Administrator and a User.
EDIT: After I posted the above, it occurred to me to check the file dates in the above folders. Only files in C:\ProgramData\Microsoft\OfficeSoftwareProtectionPlatform had dates that coincide with the Office 10 SP2 update. This indicates that only this folder was causing a problem installing the update.