Fix PHP application

We have a custom PHP application that has started having problems after moving it from one server to another. We are getting errors related to dates as follows: "Warning: date() [[login to view URL]]: It is not safe to rely on the system's timezone settings. You are *required* to use the [login to view URL] setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/Chicago' for 'CDT/-5.0/DST'" It also kicks us out of the application after each entry, requiring the user to log back in (something related to sessions) It also has the database information hard-coded in to every php file, instead of passing them from a configuration file. We need the errors fixed so the date and session problems are resolved, need the database information passed from a configuration file to each part of the application, and need any deprecated PHP code brought up to current standards. The application consists of 12 primary php files and some sub-files. Most files are less than 100 lines of code. We need this fixed very quickly as our client uses it daily and is currently not able to use it. Please include "Serious" in your bid so we will know you have read this entire description.