GET-request like: http:site.ru/result?date=27/06/2013

Tell me, please, GET-query makes a request to a script in the address bar.
request like: http:site.ru/result?date=27/06/2013
respectively, instead of the page http:site.ru/result, get a 404 page. If I remove the slashes in the date, ie to the form http:site.ru/result?date=27.06.2013, then everything is OK. But the script from another site, so I can not remake the request. This date is late. Maybe i can somehow limit the length of the link that reads the engine when the page opens
How can I correct so far?