Could well be.
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172
Check if you have Win XP SP3. Try installing it using a different browser and check.
Try 1.7.2 as sjpt says. Version 2 also doesn't like older AMD processors apparently. I had a similiar problem until I uninstalled V 2 and installed 1.7.2
Thanks for your message. I did install 1.7.2 and was able to download a book from our public library. However, when I plug in the Nook to my computer it does not appear on the on the digital editions screen so I am still unable to download it to the Nook.
Any other thoughts?
If the book is readable in digital editions then your first problem has been solved. There are a lot of comments about problems with the Nook and several solutions in other threads. If none of them work then ask another question, there is a lot of help available on this forum.
Is it a dedicated Nook eReader, or a Nook tablet?
For a tablet you some sometimes need to 'sideload' the .epub file; that is to copy it from the PC to the Nook using a file manager such as Windows Explorer. As long as[a] you have Adobe DRM compatible ereader software installed on the Nook and [b] that is registered with the same Adobe ID as your PC, you should then be able to read the file on the Nook.
Bluefire is one such app I have found good. There may well be one preinstalled on any Nook tablet (???).
For a dedicated eReader, you should also be able to sideload to the reader the same way; but might have problems getting it registered to your Adobe ID without ADE being able to see it. My dedicated Sony eReader needs Sony software installed on the PC before ADE will see it. Installing the Sony Reader software also installs a driver; and that driver enables ADE to 'see' the Sony even if you never run the Sony Reader software itself. It shows up as a drive without the driver software, but not as an eReader device. Maybe there is some similar stupidity with Nook eReaders?