Sheet does not allow data entry and recalculation

Started having this problem yesterday.
If you try to input a number for recalculation you get error message of
"The server has encounter an error and was unable to fufill your request"

The spreadsheet is here: http://sheet.zoho.com/public.do?docurl=p4oDFd59tkfcOUH2cxx6uw%3D%3D&name=gqzytlJD9tvwNdUZiLQjeQ%3D%3D

We use it to calculate Treasury yields and several other have reported it no longer works.
See group at: http://www.fatwallet.com/forums/messageview.php?catid=52&threadid=588518
If you go to last page (17) you will see two users reported it as not working as of January 16th.