If they were aimed at children he missed the mark. My 3 year old son finds C3PO and R2D2 amusing but he doesn't laugh at Jar Jar at all.
I can see that Lucas probably thought Jar Jar was funny but he is just plain annoying.
The comedy which even children get comes in the form of 3PO and R2 bickering.
It doesn't need slapstick.