Just upgraded to Domain Mapping 3.07 and site cratered.
We have multi-domains also installed, so are using dm_sunrise from that plugin pack renamed to sunrise.
I did not install the sunrise file that came with Domain Mapping 3.07.
Had to revert to version 3.05 to restore site to working order.
DISREGARD THIS ISSUE
I had left the domain mapping file for 3.05 in the mu_plugins directory and renamed it, then uploaded the new version.
The site crashed as reported, but when I deleted the renamed 3.05 file, then site works with version 3.07.
Apparently renaming the old file is not a best practice.