[jQuery] JQuery 1.2.6 and JQuery Form Plugin in IE7

I want to upload a file using JQuery Form Plugin but I have some
troubles.
It work ok with JQuery 1.2.3 but don't with version 1.2.6 and IE 7. In
Firefox2 it works great with both versions of JQuery.
* jQuery Form Plugin
* version: 2.12 (06/07/2008)
* @requires jQuery v1.2.2 or later