/cgi-system in siteurl bug

OK, my blog doing very fine, but now, when I want to log in, it seems to change the “siteurl” value in “wp_options” table. My siteurl was “http://exomel.com” and it changed it to “http://exomel.com/cgi-system”. I changed it back but every time I’m going to “wp-login.php”, it appends “cgi-system” to it. I renamed wp-login for security reasons.

Why does it do that? And, if it’s a known bug, was it solved yet?

P.S. – I’m using WP 1.3-alpha5 which I downloaded on (I think) December 15th 2004.