Error activating Nintex features via handler or stapler feature

I have a SharePoint powershell script that creates a site collection and activates a handler or stapler feature, which activates the required site and web scope features in order using their respective GUIDs. I tried activating the following features in order

   NintexWorkflow (site)
   NintexWorkflowWeb (web)

but I couldn't get the features to activate until I explicitly activated the feature that the site scope feature was dependent upon first

   NintexWorkflowContentTypeUpgrade (site)

What features do I need to activate in this method (via a handler feature) for Nintex to work? Are there additional dependencies I need to activate first?

Also we have Nintex installed on a thee-tier SharePoint farm and NintexWorkflowContentTypeUpgrade appears to be installed on the APP server but not the WEB server.

Does this matter?

Thanks,
Chris

AIHW application developer 

Nintex Workflows 2010
SharePoint 2010 SP1