[jQuery] fadeOut() not working

[Littlened]

I've created a script to fade out 2 DIV's and then fade in 2 new
DIV's.

The script works perfectly in IE, but Chrome and Firefox won't do the
fadeout. I know there isn't a problem with my code, because if I
replace the fadeout with hide, then the elements are hidden by the
browser and everything seems fine.

Is there any reason why the fadeout wouldn't work?

<script type="text/javascript">
var max_portfolio_sections = 2;
var current_section = 0;

function hideAllSections() {
     i = 1;
     while (i <= max_portfolio_sections) {
          $('#portImgWrap-' + i).fadeOut();
          $('#portTextWrap-' + i).fadeOut();
          i++;
          }
     }

function fadeIn(id) {
     $('#portImgWrap-' + id).fadeIn("slow");
     $('#portTextWrap-' + id).fadeIn("slow");
     current_section = id;
     setTimeout("portfolioAction();",3000);
     }

function portfolioAction() {
     if (current_section > 0) {
          $('#portImgWrap-' + current_section).hide();
          $('#portTextWrap-' + current_section).hide();
          }

     new_section = current_section + 1;
     if (new_section > max_portfolio_sections) new_section = 1;
     setTimeout("fadeIn(new_section);",0);
     }

hideAllSections();
portfolfioAction();

</script>