That app is not a very good app, the guy who made it admitted in his FAQ that it did not have the proper coding to work, If you are after bluetooth send/receive then use celeste
It Is very easy, make sure you also install action menu from the big boss repo and then you will get an extra send via bluetooth option or on files in ifile you can press edit and send with celeste or press and hold in your finger like you would to copy/paste and on some files like ringtones you get the option to send