help on my ollie

[cowboybebop97x]

well i can on ollie in the crack of a side-walk and when i do i get like 5 inches off the ground. when i try to ollie on a flat surface my board bolts backwards then forwards and i fall!!! any suggestions on what i can do to stop falling???

[flip]

flat surfaces are hard to do stationary ollies on, just stat them while moving and the problem will go away