I'm having the same problem! I study economics and this is a SERIOUS issue for me! The pdf creators that are installed as printers are much slower and don't convert hyperlinks from the contents list so I'm actually considering going back to Vista if this isn't fixed soon
The problem arises as soon as a single equation is entered in a document. Even if it's just an eq sign ('=') or something similar. If you convert it to an image or conert the document to a 97-2003 version there's no problem... I don't know if it's ok if you print the document on a printer...
I've found no clues on the internets as to what people are doing... If anyone's having the same problem, please write so that Microsoft will know about this. It's probably driver
path etc. that has been changed in 7 compared to vista which the office team needs to be made aware of.