I am having the same problem -- same error message, using -- suddenly, using 8.3. I created LiveCycle forms in 8.1 some 6 months back but now in 8.3 I have retrieved the old docs to see this new problem. However NO ONE has answered my post!!
I got the error message trying things on IE8 but in Firefox 6.1 things just freeze or blow up.
Did you solve it? It appears no one knows the answer.