I found a solution to the specific issue now. By experimenting, I noticed that I could just point the existing dbpedia-proper-noun-extraction enhancer engine to my own index, as a hack. This worked. Subsequently, I copied over the exact configuration settings to my own enhancer. Turns out, it was the Type Mappings section that was populated by default. After removing all the type mappings from my enhancer configuration and restarting the Stanbol server, my enhancer became available.
Thanks for your help! Still, if anyone knows how to properly debug an unavailable enhancer, please let me know. Manuel
