I’m still not sure why the underlying problem occurred but after work on developing a project specific document review workflow and trying to publish it from SharePoint Designer 2010 we received the following error“SharePoint Designer encountered an error generating the task form. Server was unable to process request. –> Activation could not be completed because the InfoPath Forms Services support feature is not present” i.e.
After investigating further similar posts indicated that it had something to do with features that hadn’t been activated. I was sure all the relevant features were activated but to be on the safe side I checked that it wasn’t directly permission related by opening SharePoint Designer on the project site and attempting the Publish the workflow with the farm admin account. No joy, same error. Next I checked the Central Admin config and confirmed that all available features were enabled at the Web Application level and that nothing had happened to the InfoPath Forms Application Service. I then checked and confirmed the 2 relevant features (SharePoint Server Standard Site Collection Features, SharePoint Server Enterprise Site Collection Features) were enabled at the Site Collection level. I then verified that the equivalent Site level features were enabled.
So far all good so there was no standard environmental reason for the failure of the publish of workflow to fail.
One post I found, whilst not directly related to SharePoint Designer publishing process, suggested restarting the InfoPath Forms Services support feature, not generally visible but responsible for providing the plumbing for supporting publishing InfoPath Forms.
Disable-SPFeature "IPFSSiteFeatures" -URL "http://yoursitecollectionURL"
Enable-SPFeature "IPFSSiteFeatures" -URL "http://yoursitecollectionURL"
Once I had run the cmdlets to stop and then start IPFSSiteFeatures for the PWA site collection I was then able to successfully complete a publish step for the workflow in SharePoint Designer.