ezRPG is a free PHP game (engine) which can be customised however you want, since it's open source.
ezRPG is mainly a very basic RPG (see features), and to make it into any other type of game (strategy, pet, etc.) would require a large amount of modifications and additions to the code. I'll leave that up to you :)
The files are all hosted on the Google Code website, however, there are different packages that you can download. To get more information on what to download, read this page: Download
The first thing you should do is search this website to see if there are already any pages that deal with your problems. If not, try asking on the Forums instead.
First of all, make sure you have read the instructions correctly!
If you get errors about file inclusion, you might be missing ADOdb: Connection Problem
If none of that has helped you, then make a topic on the forum to ask for help, and somebody will help you as soon as possible! Remember to describe the problem, and if possible, quote the error that is displayed.