Hi! As Mr. Jack Purdum stated in an earlier post, to work properly, the Arduino IDE wants your sketch to reside in a directory with the same name as your sketch, in our case "ubitx_20" because our main file is ubitx_20.ino. So you create a folder with this name and put inside all the files you find in the source code, there are 7 files if I remember correct. Now it should compile at least. If it's not uploading I think it has something to do with wrong settings around the Arduino board (driver, port number, board version, bootloader version, etc.). I hope you will get through. And by the way, CAT kontrol works also with the factory firmware. Good luck!