Using Infragistics while working with  WebUpload I faced following issues and here are the solutions for them.

Error:
The Infragistics WebUpload requires jQuery to be loaded.

Solution:

You have missed including the Jquery.js file download it form  Jquery Website

Error:
The Infragistics WebUpload requires its own script to be loaded.

Solution:
You are missing including the Infragistics.js located in ig_ui. Search  for ig_ui folder on you system and you will find it where infragistics installed files are located. Include this in your project


Its better to read the Webupload Overview at Infragistics