Attempting to upload files throws an uncaught exception

Steps to reproduce:

1) Open the uploader demo page
http://build.fluidproject.org/infusion/components/uploader/html/Uploader.html

2) Add some files to the file queue

3) Attempt to upload the files

Notice that an uncaught exception occurs

Error message:

uncaught exception: Call to SetButtonDisabled failed
anonymous("SetButtonDisabled", [true 0=true])swfupload.js (line 449)
anonymous(true)swfupload.js (line 685)
anonymous()SWFUploa...anager.js (line 118)
anonymous()Fluid.js (line 594)
anonymous()FileQueue.js (line 152)
anonymous()DemoUplo...anager.js (line 130)
anonymous()Uploader.js (line 557)
anonymous(Object originalEvent=Event click type=click)jquery.js (line 2693)
anonymous()jquery.js (line 2468)
[Break on this error] (no source for )
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