Resolved
Reported for: Toolset Maps 1.2.1
Resolved in: Toolset Maps 1.2.2
After activating Toolset Maps, a Google Maps API key is required. If Views plugin is not activated, saving key fails and throws an error.
This problem will be fixed in the next version of Toolset Maps.
On the meantime, download this file, extract it and replace the file in /includes/
folder of your Toolset Maps plugin.