The Sphider search is an interesting piece of software that embeds a search engine on your website. The original code broke when php was upgraded and has never been fixed. Pay for versions are availiable. Fortunately a free version is maintained at worldspaceflight. I have managed to install this version but have had my share of problems with the lite version.
If you get this message: Logging option is set, but cannot open file for logging.
Set the directroy admin/log persmission to 777.
sudo chmod 777 admin/log