FSEconomy uses airport data based on "Microsoft Flight Simulator 2004". As a result, many of their airport identifiers have been changed or no longer exist. This page may be helpful to find the current identifier or see airports that are no longer operating (http://myflightroute.com/fseairports.php).
Anders S wrote:Or is it allowed to land on closed airports on pilotedge or not?
Seeing as how it is a closed airport... it is likely a glass G airport... therefore, fly VFR to it and ATC doesn't even need to know that you are landing there.