Ok had to register so I can answer your question.
When you download epud/pdf or any other type of files to your Nook Color through your email via the browser but it doesn't open; you have to then locate the file by going to:
Library > My files > My Downloads
Inside My Download folder you should be able to find anything you downloaded to your Nook Color.
Hopefully this helped
*Had the same issue and didn't know how to open it when I downloaded files through the browser in my Nook Color.
So I google'd it, and found your post after I found the way to open the files 