Absolute positioning is being overridden by somethingie

Please look at this page:

http://rowby.com/demo/new-index.html

Specifically the right column.

I'm revising a site built by someone else -- and need to figure out why the division called "thirdcolumn" insists on being high on the page, even though locally I have moved it down lower in the page, so that a new piece of text can be on the top.

You can see the overlap.  Something is overriding my "div"...  It looks fine locally -- until I preview it in Dreamweaver or ftp it to the server.

I've searched the (rather large) site and found three places where the word "thirdcolumn" appears.Two  of them are in  external style sheets. And one is an external javascript file.  

Basicaly I would like to just use absolute positioning to place "thirdcolumn" wherever I want on the page. (I need to stick with absolute positioning, on this site for various reasons.)

The javascript is short.  Here is the complete external script and it's named: navbar_height.js    

--- start of javascript file below----


function setHeight() {
  var content2H;
  var content3H;
  var thirdH;
  var navbarH;
  if (document.getElementById) {
    if (document.getElementById('content2')) {
      content2H = document.getElementById('content2').offsetHeight;
    } else {
        content3H = document.getElementById('content3').offsetHeight;
        thirdH = document.getElementById('thirdcolumn').offsetHeight;
    }
    navbarH = document.getElementById('navbar').offsetHeight;
    if (content3H) {
      if (content3H>=thirdH) {
        newH = content3H;
      } else {
          newH = thirdH;
      }
    } else {
        newH = content2H;
    }
    if (newH>navbarH) {
      changeH = newH -navbarH;
      document.getElementById('navbar').style.height = navbarH+changeH+'px';
    }
  }
}

----- end of javascript file


Below is the relevant snippet from external stylesheet #1:  NAMED styles.css

----- end of snippet   ---

#thirdcolumn { /* Right column on 3 column pages. */
  left : 576px;
  position : absolute;
  top : 274px;
  width : 193px;
}

----- end of snippet   ---

HEre is the relevant snippet from the second stylesheet: styles.css:

---- start of styles.css snippet ---

#thirdcolumn { /* Right column on 3 column pages. */
  left : 585px;
  position : absolute;
  top : 92px;
  width : 193px;
}

---- end of styles.css snippet.

Any help appreciated!

Thanks!