Drop-down menus stop working

When I enable one of the plug-ins (eg. DropShadow or CurvyCorners), and add some code, my primary menu's drop-down menu stops working.

• I'm using the Giordani theme, a variant of the Marinelli theme
• I have a mixture and second and tertiary drop-down primary menus, none of which now work
• I've enable the Drop Shadow plug-in (also tried with curvy corners), and added to the Site configuration / JQuery EyeCandy admin page, the following working code:

  CurvyCorners plug-in code
  

  $(document).ready(function() {
   $("#page").corner();
});
  
  Drop Shadow plug-in code:
  
  $(document).ready(function() {
   $(".sitetitle").dropShadow();
});

• My Drupal 6.12 installation is using jQuery 1.2.6
• As a side issue, if I disable just the curvyCorner code, the position of the drop-shadow changes.