you could also try setting the left and right margins in the content div to auto:
#outerWrapper #contentWrapper #content {
margin: 0 auto 0 auto; /* Sets the margin properties for an element using shorthand notation (top, right, bottom, left) */
padding: 13px 13px 13px 13px; /* Sets the padding properties for an element using shorthand notation (top, right, bottom, left) */
text-align:center;
}