Free extensions for Joomla!

Hi there!

I need to update the newer version, when i do a regular install i get an error that the current version is used, i just need to replace the files that will allow me administer the FN_author_alias... how do i go about doing this?
shoould i open the zip and replace files via FTP?

thanks!
Merry Christmas and a happy new year!

wish u guys the best 2010
take care,

Joe