screen flickers in 2 player mode

The game is "snowboard kids", it works great on single player mode. But when I play 2 players mode, which divides the screen into upper and lower half, it started flcikering/flashing between black and the actual image.
Mario Cart works fine on 2 players mode though.

PIII 650 MHz
Win Me
GeForce2 Ti

It worked! Thanks for the help pilm.