How do i get rid of my snowboarding mental block?

ok, so my mental block kicks in when i go to the park. i've hit the rail before, but for some reason i just can't escape the fear of my board getting stuck or catch some ice on a jump and end up wiping out big time that will get me hurt. I can snowboard down pretty much any slope, but i can't get the courage for the park. What do i do?