I have installed this module however the icon "shipping_rfq.gif" does not show (dreaded red X).

includes/modules/shipping/rfq.php has the following line:
$this->icon = DIR_WS_ICONS . 'shipping_rfq.gif';

However, when I view the source of the displayed page it shows as:
<legend>Request Shipping Quote&nbsp;<img src="DIR_WS_ICONSshipping_rfq.gif" alt="Request Shipping Quote" title=" Request Shipping Quote " width="100" height="80" /></legend>

The icon is in the images/icons folder.

Can anyone help?