Are you all still sure you know why you are using this old thing?
This code is from 2005 and the author hasn't supported it/added a new version since then. There are now 90 odd "versions" most adding their own new bug.
I used to support this but I wrote a totally new version Ultimate Seo Urls 5 for your benefit which is PHP 5 code and rewritten from the ground up.
PHP 5.2+ ONLY ( PHP4 NOT supported )
The now "old" version ( first release June 2009 ) has not had a new bug reported since December 2009. Works on Windows as well as *nix and supports the "worthwhile for SEO" contributions. Adding new contribution support modules is also exremely easy as they are modular themselves.
Very important USU5 and the PRO version can replicate and/or 301 redirect the old seo urls so you do not have to lose any indexing/PR
The new PRO version is a different world there are too many features to mention here see the comparison
If you run a multi language shop then USU5 PRO is the only option as for the first time EVER your site can be individually indexed seperately for each language.