By default the F and R keys should cycle though the skill bars (though one person with this problem said even the option to change those disappeared - should be Options, Controls, near the bottom of the list, 'Previous Skillbar' and 'Next Skillbar', just above 'End turn' and 'Show world tooltips').
I still have the option to change them and as I said have tried to change them to different buttons (it accepted those changes) but the buttons still do not change my hotbar. Neither do the manual "up/down" buttons on the hotbar itself.