[pdftex] new pdftex warning

[Johannes]

ok, so i tried to produce the warning again and:
   it worked without warning when the pdf consisted of only one page,
   i got the warning again when it was a multipage pdf

information on the pdfs:
printed:
   pdf producer: Acrobat Distiller 9.0.0 (Windows)
   pdf version: 1.5 (Acrobat 6.x)
   application: PScript5.dll Version 5.2.2

Visio:
   pdf producer: Microsoft Visio 2010
   pdf version: 1.5 (Acrobat 6.x)
   application: Microsoft Visio 2010