Don,
If you access the 'Service Details' under the Layer Details dialog, does the REST page say true or false for "Has Attachments?"
I would also mention that as of December 10th, ArcGIS Explorer Online will be moved to �??Retired�?? status, meaning there has been no active or continued development of the software since 2012 and users will no longer have access to technical support through direct phone, chat or email request. Access to limited support will remain through discussion forums and knowledge base articles.
If you can share your service URL, I'll be happy to take a look at it.
- Daniel