1) Is the "onsubmit="return validate()" calling javascript properly -- ie, is the "return validate()" in the same page with the form? Is the validation returning what you expected? (My js fu is very weak, but the space in that function name makes me itch).
update Same question if you're calling a php function, if that's the case, as belated reconsideration suggests?

2) When you see the script returned in your browser, does the address bar include the name-value pairs you think you're submitting?

3) (Style, perhaps) Is there are reason you're using "get rather than "post" in the form?