#40 correcting core_name variable and adding error message
#40 correcting core_name variable and adding error message

@MBoustani - Can you review please?

MBoustani/GeoParser,memex-explorer/GeoParser,memex-explorer/GeoParser,MBoustani/GeoParser,MBoustani/GeoParser,memex-explorer/GeoParser,memex-explorer/GeoParser,memex-explorer/GeoParser,MBoustani/GeoParser,MBoustani/GeoParser