Nice, they have added hash info.
You can tell how often I visit my account page.
 

Saves going to the tamberine man..

If by chance you happen to have the same unzip package the installer is using (like winrar) for example you may need to open your copy and select keep broken files.
 
Run full antivires and then disable it.
 
If files are getting changed on download it is likely a virus or filesystem issue. Flakey RAM can also cause this issue. If you are getting the files from command center it is not the files ;)