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Apparently you will get this error if you have more than 50 items in your hulu queue. I had 120 items. I logged into the hulu web site and reduced the queue down to 5 items and hulu plus started working on my Tivo. Technical support said they are working on an update so you can have more than 50 items in your queue. He said until then keep it under 50.
I told him I missed a week of the 1 month free hulu plus trail due to this issue so he credited me 1 month of service which was nice.