Missing fonts in .pdf file

[Gilbert van den Dobbelsteen <gilbert@panter.soci.aau.dk>]

Not much of a context question, but I'll give it a try:

The guy from tghe prepress bureau came by, returning my .pdf file, because
the fonts were missing. Well, that is not entirely true, because they look
good on the screen, but using Acrobat 5 (on a Mac) the print-out on the film
machine displays Courier on some pages. The metrics are correct, but the
face isn't!

And now the circumstances:
- pdfeTeX (Web2c 7.3.3.1) 3.14159-0.14h-pretest-20010210-2.1
- context version: latest (not beta)

The .pdf file is constructed from seperate .pdf documents. These documents
came from several universities and were created using a lot of different
tools. I am using context merely as a page-impositioner here.

So guys what is the problem? Is pdftex? Is het Acrobat on the Mac? Or do I
need to pre-process all the seperate .pdf files using gs or something like
that?

Please help out

Sincerely Gilbert.