I talked to the publisher again and he said that he would send me the exact
error message, but I have not received it yet.  But he did say that his
printing shop wants the ability to download just the header information from a
pdf rather than the whole pdf file which may be up to 80 mbytes.  From that
header information they will have the ability to render individual pages
rather than the whole document.  For example, they could request page 264 and
render that single page as a jpeg.

Note that this is information from the publisher, not the printing shop that
is doing the work, so technically, the publisher's jargon may be inaccurate,
but a basic understanding of the needed functionality is there.

When I get specific information from the printing shop, I'll pass it along.