Fatal error with Domain Mapping plugin

Since enabling the Domain Mapping plugin, when I visit my primary site (bibliogalactica.com), I only get this message:

Fatal error: Call to a member function get() on boolean in /home/ryanw282/public_html/wp-content/plugins/domain-mapping/classes/Domainmap/Module/Mapping.php on line 1117

I've read through the documentation but have been unable to resolve the issue. I've configured the wp_config file, I have a dedicated IP, and I haven't added another domain yet.

Thanks for any suggestions you can offer. I have enabled support access.