Ed,
I haven't heard of anyone with similar behavior to this (ADE freezing).
Please open a Digital Editions 1.5 Technical Support case. Use the contact links at http://www.adobe.com/support/digitaleditions.
You'll need to generate an error log for your case. Please read
"Enable error logging in Adobe Digital Editions 1.5"
http://www.adobe.com/go/kb403740
Regards,
Bentley Wolfe
Senior Support Engineer, Flash/Flash Player/Digital Editions
Adobe