The FrontPage Search Component is implemented to use Microsoft's Indexing Service on Windows 2003 (previous iterations supported a FreeWAIS implementation, but no longer do).  3Essentials has found  an incompatibility between the Plesk Control Panel and the Microsoft Indexing Service, and as a result, 3Essentials has disabled the Indexing Service, effectively removing support for the FrontPage Search Component.

We do however provide an easy to use alternative in the form of an ASP based search function for your site.  You can find this ASP based search function in KB article 165