自分の環境(Firefox/Chrome)で以下のURLを踏むとhttp://www.bbspink.com/404.phpに飛ばされます
http://babiru.bbspink.com/test/read.cgi/hnews/1108623978
http://babiru.bbspink.com/test/read.cgi/hnews/1108623978/
http://babiru.bbspink.com/test/read.cgi/hnews/1108623978/181
http://babiru.bbspink.com/test/read.cgi/hnews/1108623978/181n
余談ですがhttp://www.bbspink.com/404.phpはぴんくちゃんえるなんですね