Pass Parameters via URL

I had to do some research to find out why my URLs did work. In short, the URL should point to http://localhost/ReportServer/ instead of http://localhost/Reports/, which is the Report Manager. Here is the post that helped:
http://dobrzanski.net/2008/08/11/reporting-services-problem-with-passing-parameters-directly-in-the-url/

Here is another good post about passing multivalued parameters:
http://bobp1339.blogspot.com/2007/10/passing-ssrs-report-parameters-in-url.html