Microsoft Fix it 50528 error
It is possible that the Fix It tool won't run on the machine you're attempting to fix if it doesn't meet the requirements for the OS (ie. Windows XP versus Windows 7 etc.) as well as the service pack.
Here's the link to the particular KB page you need: http://support.microsoft.com/kb/822798
If you are experiencing the symptoms on the KB page, but the Fix It tool won't run for you, try making the fix manually – the steps are outlined after the link for the Fix It tool.
As always, before you make any changes to your system, you should do a back up, and depending on the version of the OS, create a restore point.
I hope this helps.