The message that you are getting that says "GeoDBSetup.exe is not a valid Win32 application" is probably because:
Your download of the LegacyGeoDBSetup.exe file was incomplete or corrupted.
Or, hardware incompatibility (not as likely, but a possibility).
If the GeoDBSetup.exe file is corrupt, incomplete or missing, Windows will be unable to execute the file and may generate this error message, or other messages.
Please download and save the LegacyGeoDBSetup.exe file to your Desktop by downloading from our alternate site: Geo Database Installer - from Alternate Server.
Next, reboot your computer in Safe Mode; then logon to your computer as Administrator and install Legacy using the saved LegacyGeoDBSetup.exe.
Temporarily disable your Internet security (firewall, anti-virus, anti-spyware, anti-adware, popup blockers, etc.) as these programs can sometimes remove critical system files from Legacy.