You could try looking in the connection box on the panel - if it gives access to the midpoint of the panel - i.e. 17v then it may be possible to electrically split the 34v panel into 2 x 17v panels and connect in parallel.
Otherwise it may be simpler trade in either the inverter or panel for compatible ones?
Or use an MPPT controller to drop the voltage - but this may be an expensive solution and electrically inefficient as your converting voltage twice.