Basically, this error is telling you that the Joint1 Rotate X attribute in the control panel has some node attached to it. This will be either due to you having already binded the skin to the skeleton or some other node already working on it.
To reset its rotation this should be done for every joint that requires it prior to binding the skin. So unbind the skin and then try again.
If not let us know.
Chris (formerly R@nSiD)
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Winner SM VFX Challenge 1
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