CSS: How to make an image-border

I'm trying to place a border image around a div. I followed the hints on css-tricks but I can't get it to work. This is the page: http://darylkeep.com/aanbod/

EDIT: I get four little borders in the corners instead of one around the whole div. Why is this?

I'm also wondering if this is still the way to go to do this since I haven't run across this property before. Is there a better way? Thanks in advance.

<div id="main-content">stuff</div>

#main-content {   
  margin-top: 30px; margin-bottom:30px; padding:20px 20px 20px 20px; width:80%;
  background:rgba(255, 255, 255, 0.7);  
  border-image-source: url(www.darylkeep.com/wp-content/themes/darylkeep/assets/images/wiggly_border_full.png); 
  -moz-border-image-source: url(www.darylkeep.com/wp-content/themes/darylkeep/assets/images/wiggly_border_full.png); 
  -webkit-border-image-source: url(www.darylkeep.com/wp-content/themes/darylkeep/assets/images/wiggly_border_full.png); 
  -o-border-image-source: url(www.darylkeep.com/wp-content/themes/darylkeep/assets/images/wiggly_border_full.png); 
  -ms-border-image-source: url(www.darylkeep.com/wp-content/themes/darylkeep/assets/images/wiggly_border_full.png); 
  border-image-slice:2,8% 1,7% 2,8% 1,7%; 
  border-image-repeat: stretch;
  border-image-width:100px;
  border-width:50px;
  border-style: solid;
}

Solution

CSS

div{
width:300px;
height:auto;
padding:25px;
border:10px solid #999;
text-align:justify;
position:absolute;
top:25%; 
left:35%;
border-image:url(Light-green-elegant-embossed-frame-rectangular-powerpoint-border.png) 20 repeat;
}

HTML

<div>
It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).
</div>