Pamela,
Do the files show up in the Files section after you upload them?? Does the error occur when you click on a file to open it in your browser?
This group has a PDF file in its Files section - can you view that?
What browser do you use?? Do you have a PDF file viewer installed and configured in your browser?? Can you view PDF files in your browser from other web sites?
Thanks
Toby
Toby Kraft