I recently try to install IIS (via features) and PHP 5.6 for IIS via WPI.
Installing PHP along with other PHP extensions went smoothly, but installing PHP Manager for IIS failed immediately.
Check the log and get this
MSI install return value for product 'PHP Manager for IIS' is '1603'
- Make sure you have .NET Framework 3.5 (includes 2.0 & 3.0) installed
- Change HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters\MajorVersion to 8
- Run MSI or use WPI to install PHP Manager
- Change HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W3SVC\Parameters\MajorVersion back to a (10 in Decimal)