Hi,
Please, try moving the SDK (zip or folder) to an empty folder. After that, test command line modifying the following lines in your property file (sdk.name will depend on your SDK version):
Comment/remove this line:
example.xml = C:/Projects/frdmkw38_beacon_freertos/DebugMKW38A512xxx4.xml
Modify these lines:
sdk.name = SDK_2_6_15_FRDM-KW38
board.id = frdmkw38
Please let me know your results.
Regards,
Eduardo.