your friend is right, flush the fluid but you should only use genuine honda atf. this transmission is quite sensitive. the best bet is to use honda atf. they are about 9 bucks a quart and you need 3 quarts to do a drain and refill. for a complete flush, which a lot of people don't recommend, uses about 9, i think.
after you change your fluid, reset the ecu and see if the codes come back. but looking at these codes, it does not look good. sorry