If you want to edit the menus, look for the following code (and similar, since the category reference will change) and delete it.  You will have to do this every time you generate the navigation:

<img align="absmiddle" name="IMGCAT2" border="0" src="images/btn_expand.gif" onclick="javascript:UpDown(2);">

 

If you want a more permanent solution so that every time you generate the category navigation those icons will not be present, it is necessary to edit the code in the generator script.  If you attempt to do that, making a backup copy of the working version would be a good first step.