the airport in your flight plan must be a part of the airports file after you decompile . you can take some new australian airports from this file "australia regionals http://ftp.avsim.com/library/index.php?Sort=Name&ScanMode=&CatID=fs2002ai&Go=Change+Category
type australia and search -its the third download from top.
ad them to the airports file ,compile .
then decompile and add youre flightplans .and compile again (zzz zzz zzz zzz)
you might as well add the kendell and impulse aircrafts as well so the long process will be worth it.both are at AVSIM.