Ray,
It may have been easier to set the co-ordinates for google earth to decimal to save any calulations.
If you have entered it similar to the others in the aircraft table in database explorer with ICAO code, name etc it should appear when you start up. Also for 2D purposes ensure you have the outline for the airport in your outlines folder. If not download the outlines file from Rods website
http://rodb.gofreeserve.com/RadarBox/Downloads.htm and extract them into the outline folder.
Just in case, here are the entries
p4 EGCN, P3 DSA, pn and pc Robin Hood Doncaster Sheffield, ps England, pt United Kingdom, pm 0, pa 53.474722, po -1.004444
When you switch on it should all be there.
Alan