Bruce,
Like Doug, I do not use Linux or iOS with either of the fl programs you listed, so cannot comment on your specific error messages (though most of the time they are permission issues in Linux systems).? I have connected a v4 uBiTx to a Raspberry Pi running WSJT-X.? In your case, I would go back to the fldigi and flrig setup and verify that you are not trying to use DTR or RTS signals, as the uBiTx does not support those hardware signals.
Verify the settings in the digital interface programs to match what Doug displayed in his post.
Just a suggestion.
73
Evan
AC9TU
