Get "'<Toad installation .exe file name>' is not a valid Win32 application" when installing (4311413)

Error:

" '<Toad installation .exe file name>' is not a valid Win32 application"

e.g "'Toad for Oracle 9.7.2.5 Commercial.exe' is not a valid Win32 application"

is displayed when launching the executable that is downloaded from Quest's web site.

This is a general Windows error, likely due to a corrupted file.  The corruption can be caused by a firewall blocking portions of download from being downloaded.  You can see that this is happening by comparing the size of the file listed on the web site and the actual size of the file after download.

RESOLUTION #1:
Download the installer file again. 

RESOLUTION #2:
Configure your firewall to allow Quest's installer through without any portions being blocked.

RESOLUTION #3:
Download from a machine that is not on your network to get around firewall (i.e. from your home).

RESOLUTION #4:
Contact Quest Support and ask to send you the installation file via FTP link/site.