Digital Editions cannot connect error

Hi I am using Windows 7 32bit with Sematec system protection. When I try to get a book file into Digital Editions I get an dialog box that tells me that Digital Editions cannot connect, to check my internet connection. My internet connection is wireless to a Comcast modem/router. I have gone into Sematec and Disabled the firewall and I still get the no connect error. It never opens the book file into Digital Editions window. What has me locked out? Art  arossi10@yahoo.com