I have described how you get the error messages you mentioned. There are many ways to get the error message (just pressing buttons at random will get one sooner or later), but the principle of the wrong procedure that leads to the error message remains the same. Without you describing the exact details of the buttons and the order you are pressing them, in relation to the tracks and measures of the song you are using, it is impossible to say where your particular problems occur.

If you copy and paste to increase the length of the song first, before punching, you are far less likely to run into these kind of errors, since many are due to incorrect stop and end commands in relation to the punch in measures you are attempting to overwrite. The solution is either copy and paste beforehand, or step record edit the commands afterwards.

Try this:

Press Easy Record then OK.

play 5 measures of chords and melody then stop after measure 6, then rec stop.

Press Sequencer, record & edit, punch record.

set all 6 tracks to rec.

Press start and listen to what you have recorded.

at measure 6 start playing some more chords and melody.

press ending, then rec stop.

What could be simpler than that?