Here is a description of the files you need to make Underfoot complete. You will need a client patched to live, or a different client like Titanium/SoD to copy them from.
http://www.eqemulator.net/wiki/wikka.php?wakka=UFMissingFilesListIf you don't have another client, and assuming you purchased Underfoot recently on Steam, your best bet is to make a copy that you will use on the emulator before doing anything else, then patching the Steam copy live while your free time is still active and using those files to fill in the missing pieces.