I start using MS Office 2007 and also has Adobe Acrobat 8.0 install, I can print as PDF in MS Word 2003 but not with MS Office 2007. See below screen shots of error:

But in fact with MS Office 2007, Microsoft has provided an add-in for converting from DOC to PDF very easily, just download from: http://www.microsoft.com/downloads/details.aspx?FamilyId=4D951911-3E7E-4AE6-B059-A2E79ED87041&displaylang=en

After I install: SaveAsPDFandXPS.exe
I can convert by go to: Save As -> PDF or XPS
PDF loaded as expected!