duxa wasn't messing up your installation most likely, there's really nothing it could overwrite that would damage your client even if you installed it incorrectly
it was probably due to a random error involving internet connectivity, where you connect to the server initially, load into char select, and then lose your connection at some point and it displays a message saying your spell files are out of date. (at least that's what I'm guessing is happening after experiencing it over the years)
If you are sure you've patched your spell file correctly, and you still receive this message, it means you're not fully connecting and you need to restart your client, and preferably your internet connection/router/etc.
Here is a link to the spell files :
http://www.project1999.com/files/P99Files36.zip