In the rare event that this occurs, check your firewall security options.  Be sure that they are set to allow access to the following domains.

NTGreek In Diagram Members: http://www.inthebeginning.org

Purchased Diagrams: http://www.ntdiagrams.com

Furthermore, if you are a NTGreek In Diagram member, be sure to select "Membership (All Diagrams)" from the drop-down menu under "Secure Login".  Your user name and password will not work properly for individual diagrammed sets such as The Epistle to the Romans.