From NS4?

We are getting the following two errors in the javascript console on the onmouseoff command:
JavaScript Error: http://oldmember/library/js/mmenuns4.js,
line 16:
_mi[_cel] has no properties.
JavaScript Error: http://oldmember/library/js/mmenuns4.js,
line 16:
_mi[_cel] has no properties.
We have no main menu and the (2) menus are being shown with the following code:
<td><a href="#" id="gl2" class="glink" onMouseOver="popup('aboutmenu','gl2')" onMouseOut="popdown();">About</a></td>
We didnt want to use the image reference method ( http://www.milonic.co.uk/menusample.php?sampleid=24 ) as we only have two drop downmenus in our nav out of nine main nav items and that threw out the layout, and we didnt use a main menu because our design couldn't be satisfactorily mirrored with the menu styles.
We need help very soon, as this sit eis due, and we will have to inform our client that the fantastic menu software we advised them to purchase a license for them to buy isn't able to work satisfactorily on NS4 even though we said it would ... making us all look bad
