Wrong departure ICAO code

Try to make atc file for EGCJ whatever I do ,I keep getting "wrong icao code" when i fill in the flight plan.
There is traffic .
Where does the atc gets the data for making a flight plan?
The dat file is made from the default apt.dat in WED.
Importing the flightplan from JAR A320 same "wrong icao code".I made several succesfull atc routes but this is a mystery to me.