I am having a problem with the thermostat wiring.[240 volts] I have the two black wires from the thermostat wired too the two black wires on the heater,the two red wires on the thermostat connected to the two feed wires from the panel.when I turn on the breaker it kicks the breaker off.what am I doing wrong?

You have two circuits going through the thermostat (which is just a temperature sensitive switch) one red and one black.
Connect one red to the line. Connect the other red to the heater. Do the same with the black.