I did correct the spelling (after face palming myself for making the mistake in the first place). I also tried leaving the default values created by the PDF. I get the same error.
Can you send me the XFDF after correcting the class name? I can't seem to reproduce the issue after manually changing the class name in the XFDF you linked.
I somehow managed to get the sheet working by starting it over from scratch. Thank you for looking into it and finding my spelling error. I did find very specifically that using the background "Pirate" causes an issue though (it happened on 2 different character sheets).