A program cannot set default issue to open in Win7 (File Association)

It is because this software pointing to isn't registered correctly. (Since in Windows 7 all 32bits software will be in "Program Files (x86)", instead of "Program Files")

The solution is change the follow registry in "Computer\HKEY_CLASSES_ROOT\Applications\"

[HKEY_CLASSES_ROOT\Applications\ABC.exe\shell\open\command]
@="\"C:\\Program Files (x86)\\Innov\\ABC.exe\" \"%1\""

And then go through the "regular" process to associate a program with an extension.

For more information:

http://answers.microsoft.com/en-us/windows/forum/windows_7-files/problems-with-file-association-in-windows-7-64-bit/8a84fcec-22df-4942-8e35-d98dbe96e327

A program cannot set default issue to open in Win7 (File Association)