I have noticed a few questions on forums.iis.net related to being unable to install PHP Manager using the Web Platform Installer. The WPI logs are usually pretty good at showing why an install failed. In this instance, the following was listed:
ERROR : [01/24/2014 09:37:49:386] [VsdLaunchConditions ]: Custom Action failed with code: ‘1603’
INFO : [01/24/2014 09:37:49:386] [VsdLaunchConditions ]: Custom Action completed with return code: ‘1603’
This return code points to an issue with the MSI installer and I was unable to locate anything even remotely associated with what was causing the failure after multiple web searches. In the same forums thread, another user mentioned performing a manual install of PHP Manager on the same server and received a much more descriptive and helpful error. The install failed stating that .Net Framework v2.0 is required.
The .Net framework versions are not enabled by default on the newer server operating systems. To remedy this issue, use the Add Roles and Features option within Server Manager. Add the .NET Framework 3.5 Features (and any required dependencies). Once you have completed this install, you will be able to successfully install PHP Manager using WPI.