Imported graphics not exporting to XML

[Steve Rickaby]

What can cause the message:

'Cannot export graphics or equation contents. Check the element mapping and description' 

and failure to export graphics with XML export? 

I am exporting to XML without a structured application in place, as this is one-way only. (Maybe not a great idea?) The documents are all valid, and the exported XML looks ok, but as far as I can see none of the imported graphics files are exported. The majority of imported graphics are EPS format.

-- 
Steve