You could try 7-zip if your not using it already, great little program and under 1MB. Not sure on fixing it though, are you using a specific program to try and unzip or are you trying to unzip using the windows explorer looking type app built in to windows?
Tried right clicking on the .zip file and then click "Open With" and then click "Compressed (zipped) folders" ?
Unzip the fix and extract the .REG file to the Desktop. Right-click the REG file and choose Merge. Note that you need to be an administrator to apply these fixes.