If you have Panda Cloud, please do these steps:
Access the Panda Data Shield.
Select Settings.
Find the Permissions section (list of allowed & denied applications).
Find Legacy.exe (it will probably show as denied). Switch to Allow.
Run the Legacy Installation again.
Zone Alarm has also been a problem for some users. Please temporarily disable Zone Alarm when downloading and installing Legacy.
For any other Internet security programs, you probably won't have a problem, but temporarily disable them if you do.