Good. Doesn't hurt to check for simple problems.
Do the motors immediately start turning when the robot is reset?
Have you tried moving the centering dials beside the stick to center the joystick?
Are the PWM1 LEDS lit when the joystick is centered?
There is no change when you move either joystick? The motors don't reverse at all?
Both joysticks do the same thing?
Can you copy the lines of code where you read one joystick value and then
assign it to the PWM output and post it here (or send it in a private message)?