Incomplete site definitions render Magnolia CMS unusable. AdminCentral will return "HTTP Status 500" and does not render pages.

To reproduce:

1. Install Enterprise Edition 4.3.7
2. In Templating Kit > Site Definitions, copy the existing site definition "demo-project-de" as a new site definition and change its name to "example".
3. Under "example", add a sub content node "mappings".
4. Under "mappings", add a sub content node "websit" (note the intentional typo, missing "e")
5. Go to the Website workspace.
   
   

Magnolia breaks, displaying HTTP Status 500. System is unrecoverable except maybe with Groovy Rescue Console. Please make the system more forgiving regarding incomplete and mistyped site definitions.

Error message attached.