If this doesn't work, see the Q324767 article from Microsoft support.
You probably tried to patch WA when it did not need patching.
It allows installing W: A on 64-bit Windows operating systems, among others.
This FAQ is for technical problems and will only apply to users of the latest update of Worms Armageddon (v3.7.2), or users either trying to update to this version, trying to install WA or trying to access Worm NET. If you have one, try getting a refund and buying a CD version.
If you have any comments regarding this FAQ, please add them to the talk page.
Simply copy the "Autoexec.nt" file from "C:\Windows\Repair" to "C:\Windows\System32".
If your Windows is installed in a different location, replace C:\Windows with that location.