Search files for v.4

My previous hoster recently closed shop which meant I had to move my websites including my Community Server / Telligent blogs to a new hoster.  The new hoster has been great in the migration and supports Telligent/CS, but only up to v.4.1.  Also, as it turns out, they don't appear to have the files for Search functionality.

Does anyone know what engine was used, where to download the needed files etc?