Hi Duncan,

I would grab the correlation Id and check ULS logs for more error details. There you should find what is causing the issue.

Besides of this you should check 

• if all solutions deployed correctly in Central Administration -> System Settings -> Manage farm solutions, it should look like this (if you installed only workflow, then you can ignore the forms solutions):
• if all Databases were correctly created by going to Central Administration -> Nintex Workflow Management -> Database Setup, there you should at least have a configuration database created, better you install at least one content database too
• finally you should check if the license has correctly been added

If everything is good on the setup side we will need to dig into that error message by scanning the ULS logs for the correlation ID.

Best regards

Enrico

My issue was the lack of a correctly set up database.  It fixed all the issues.  Thanks for your help!