When loading the uploader demo in IE 6 it throws an XMLHttpRequest is undefined error.

This appears to be caused by this line of code.
line: 23

fluid.browser.binaryXHR = function () {
var canSendBinary = window.FormData || XMLHttpRequest.prototype.sendAsBinary;
return canSendBinary ? fluid.typeTag("fluid.browser.supportsBinaryXHR") : undefined;
};

Below is Colin's suggested fix from the fluid-work channel ( http://wiki.fluidproject.org/display/fluid/fluid-work+IRC+Logs-2010-12-14 )

var canSendBinary = window.FormData || (window.XMLHttpRequest && window.XMLHttpRequest.prototype.sendAsBinary);