My PHP doesn't work iframe'd paypal problem?

Hey so I have a problem when I iframe my widget into the sidebar of my main website it doesn't redirect to paypal?

This works just the normal page redirects to paypal
http://blitz-gaming.net/paypal

Then when it's iframed into the sidebar it doesn't redirect you to paypal:
http://blitz-gaming.net/mc/

Whats the problem?