PayPal Security

[X|ETRaM]

I setup PayPal at my webpage http://www.bellyket.com after checkout people directed to the paypal webpage. Everything is OK untill here. But when i check WebPages that uses PayPal i noticed at below there is a "lock" icon that show u are at security area. But at my webpage there is a " ! " next to lock icon. That means there is a problem with security.. How to solve it?

[Scar]

What does the warning say? Are you using SSL certificate? What have you entered in your secure url field?