Sorry for the delay in response.
Looking at the pop-up that you have got is not the error but a warning. This file is dynamic in nature and requires database connection I believe to show more contents. And this document might have been signed by some automated system.
As the message says on the Pop-up in order to sign this document you have to check with the author of the document.
Please let us know if that helps. Or if you have already found a resolution/workaround to this query, please reply to third with your findings that will help.