Hi Robert,
Hope you had a good weekend :)
The portlet facet should be enabled if the runtime it is pointing to have a JBoss portlet runtime installed in it.
If you are sure you got a JBoss portlet runtime installed then I would love to hear which one since then we might have a bug in the identification.
In any case you can disabled the facet/runtime check in Preferences (JBoss Tools > JBoss Portlet > Check runtimes for portlet components)
When that is disabled then portlet facet is possible to install on runtimes with no known Portlet implementation.
I'm actually starting to think we should make that the default since users seem to be more confused by it...