Recent PHP versions offer a mysqli extension instead of the old mysql extension. Since Nucleus relies on the
mysql_xxxx functions, it won't run when those are unavailable.
A database abstraction layer would be the ideal solution, but will take a long time to implement correctly and break most of the currently available plugins. Luckily, there is a workaround which works rather well: defining fake
mysql_ methods that delegate the work to the new
mysqli_ methods. This way, you can keep running the Nucleus core and most plugins.
Update 2005-09-28: These changes made it into CVS