Not sure if this is a multi-db issue.
I am having the problem of the module/gateways settings not saving. Also, every time I try to save the settings it keeps creating a "Pro Site" page, so I wind up with multiple "Pro Site" pages.
I have installed:
Multi-DB Ver 3.0.7
Pro Sites Ver 3.0 RC 1
If you need more info please let me know what you need.