cleaning up/rewriting dated PHP code

A former employee created an application that was for training pilots. It uses PHP throughout and needs to have some of the code fixed because I moved it to a new server and there are many errors now. Most of the errors are simple to troubleshoot - things like fixing paths or database login information. So it is really a matter of patching up errors because of moving the site to a new server as well as recoding some of it using "included" configuration files so that this is more portable in the future to another server. The are some auto prepend PHP htaccess access files I would like converted to includes/require. I expected to be at least a four-hour project to fix the errors that are currently there. I would think maybe somewhere between 4 and 12 hours to rewrite some of it to make it more portable. I would like to get someone started on this as soon as possible.