just thought I'd share an issue I had with a recent installation of Nintex Workflow.
Nintex installed fine however when we went to publish the first workflow it failed with the following error message.
soap:ServerServer was unable to process request. --->
Failed to publish workflow: <DeclarativeWorkflowDisabled/>
From research, I found other articles that reference missing elements from the web.config file, however our web.config had all the correct entries.
I submitted a Nintex support call and Simon Muntz suggested that workflows may have been disabled for the web application.
As we had inherited this SharePoint installation it turns out that had been the case and workflows disabled.
To enable, in central admin, web application.
Select the web application, click the general settings drop down from the ribbon and select workflows.
Set: 'Enable user-defined workflows for all sites on this web application?' to yes
This solved the problem for us.
Hope others find this helpful as this fix didn't return from google for myself when searching on this error message.