Redirect with user dropdown content

Nice module. It's working fine if I type the following url in my browser address bar.
"http://localhost/sports/node/add/scoreboard?edit=[field_game][key]=futsal"
I have a page type with dropdownlist, I use drupal_redirect_form(null,'node/add/scoreboard?edit=[field_game][key]='.$_POST["game"]); to redirect to scoreboard page with game value passing, however it goes to the following url
"http://localhost/sportsarena/node/add/scoreboard%3Fedit%5Bfield_game%5D%..." and just display the node/add page instead of the scoreboard page.
How can I redirect to node/add/scoreboard page with dropdown list selected by user. Thanks in advance.