Steve, I would suggest raising a ticket with Xara but before doing so try a few sanity checks.

When you drag and drop a PDF onto a Xara page, I assume you have selected the add a link option.
If you save and export the site locally, do you see the PDF in your index_htm_files folder?
Check the PDF filename isn't miles long as your service provider may be truncating filenames.
Ditto for file size.
Does it run OK under Preview Website in Xara's browser. If yo are uploading with Xara do you see the filename appear when this is happening.
Can you see the PDF filename in your Explore Web Space view if uploading through Xara on can you see it hosted in your FTP application or through the service provider's interface?

Acorn