I've saved a Word 2007 file as pdf using the Word, Save As... option. The file opens in Adobe Reader 9, then freezes. I have to End Task on the program. However, if I open Reader, then File/Open the file it is OK and I can scroll through the document. I found if I opened Reader, Help menu and did a Repair Adobe Reader Installation that it solved the problem. I had the same freezing problem if I created the pdf file using Adobe Acrobat 8, then opened it with Reader 9.
Same problem occurs at work which makes me think it must be a bug. I can't find a patch for this particular issue and I note when I did a web search that there are other users who have the same problem.
PC 1 (work): Windows XP Pro, Office 2007 both with latest service packs etc. 4gb RAM
PC 2 (home): Windows Vista Business, Office 2007 both with latest service packs. 2gb RAM
Work laptop: Windows XP Pro, Office 2007 with latest service packs. 2gb RAM