I faced with a problem using jQuery blockUI plugin.

I got an error to my console

 Uncaught exception: ReferenceError: Undefined variable: jQuery

Error thrown at line 573, column 2 in <anonymous function>() in scripts/jquery.blockUI.js:

    setup(jQuery);

called from line 15, column 1 in /scripts/jquery.blockUI.js:

    (function() {

If I try to run script I got an error no such method $.blockUI 

script is loaded, I see it in chrome debagger and nothing wrong with path to plugin.

I use jQuery 1.7.1. 

What can cause the problem? help, please