Using the jQuery Update module throws the "F is undefined" error I am using the jQuery validate module (which is mandatory for client side validation module).

If I use that module, my existing functionality is not working well. It is throwing, "F is undefined" while using minified version or, "$.ui is not a function" with the normal version of jQuery.

I understood that version plays the problem here. How do I avoid the error message?
I use jQuery Update on every site we make.

One typical problem it has, is that it can cause problems on admin pages.  The issues for the module has a patch (http://drupal.org/node/775924#comment-3010750) that fixes the problem.  You can also edit this to use any version of jQuery you want, as long as you place the proper versions in the module folder.