problem using CGI.requestURI

Hi every body,
I have a question about using "CGI.requestURI".
I want to know what is the URL of my current page, so I use this code 
in my template:
<?cs var:CGI.RequestURI ?>

but when users are came from another site to my site, RequestURI 
starts with double slashes (//) instead of single slash (/), for 
example:
//MyCurrentPage.py (instead of: /MyCurrentPage.py)

why do this happen and how can I resolve this problem?

regards,