PHP on 64 bit Windows
64-bit operating systems are becoming increasingly popular, not without teething pains though. When using IIS on 64 bit versions of Windows 32 bit applications are disabled by default. In this guide we'll look at how you can enable 32 bit support on your 64 bit Windows installation.
If you have tried running PHP on IIS on a default install of 64 bit version Windows, then you'll probably have seen this error in your Internet browser window;
%1 is not a valid Win32 application
This is because the Enable32bitAppOnWin64 metabase property in IIS is preventing the use of 32 bit applications. The solution is quite simple, simply open a command prompt and navigate to your C:\Inetpub\adminscripts directory and run this command;
cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 1
From here you should be able to run PHP (and other 32 bit applications) on IIS when using a 64 bit version of Windows.