I think Apex objects require you to add the namespace.
Michael A. Alderete

I tried adding the c namespace just in case, but it’s not working:

<aura:attribute name=”myApexClass” type=”c.NewWrapperClass” />

Also, I tried in a Dev Org with a namespace, but unfortunately I have the same Internal Salesforce Error as without a namespace:

<aura:attribute name=”myApexClass” type=”TESTLIGHTNING.NewWrapperClass” />

And yes I know, I have an awesome namespace :D