If you program in PHP, or you want to try doing so, then you'll need a development environment in which to write and debug your code. One well-known example is an excellent product called Code Lobster, and in addition to their commercial versions the company also offers a completely free edition too.
Code Lobster v5.14, Free Edition, was launched last week and it includes new features and bug fixes. Download it from http://www.codelobster.com/download.html, install it, install PHP too, and you have a complete development environment that's totally free. The Code Lobster download is around 48 MB, and the site is rated as reputable by Web of Trust. The installer triggers just one of VirusTotal's 65 scanning engines, which is undoubtedly a false alarm and can be ignored.