Please post some code from your xdf file so we know we are on the samepage. I have solved this problem before.

Your pdf wouldn't get populated with data if you are not loading the pdflocally. Unless you have some licenses or perhaps certifications,... Itssupposed to be a security risk blocked by Adobe!I found the work around to embed the pdf in the xdp file using base64encoding as oppose to linking to it.Ho...

I was wrong change MIME type helped but did not solve the problem.Opening an XDP file in browser causes Acrobat to issue the error message in my original post.Please help.