This Help topic refers to the following versions;
þ Enterprise þ Professional þ Personal þ Small Business
If PDF documents do not display in the document viewer it is possible that Adobe Acrobat is not set to allow display of PDF in a browser.
To set Acrobat to display PDF in a browser in Acrobat 7:
Go to Edit/Preferences
Select Internet from the Categories
Check the box for "Display PDF in browser".