URL issues

When trying to type in a URL into the link for banner it does not accept the URL and modifies it.

I am trying to use http://kidsgallery.com/frontend/web/index.php?r=course-category%2Fcourse&id=62, but once I press update, the URL reverts to http://kidsgallery.com/frontend/web/index.php?r=course-categorycourse&id=62

Can anyone shed any advice?

Thanks