masked textures

I am using rows and rows of flat meshes with masked textures to simulate a grassy plain in a game. The only problem is that when I select the masked flag(4) on the loadtexture function, a funny rendering error occors. It appears the some of the meshes that are farther away are being drawn on top of the ones that are closer up. does anyone know why this sort of thing would happen? if so, how do I fix it?
thanks

Are you sure you are using flag 4? The error you describe is pretty common with flag 2, alpha transparency.

no, yeah it's flag 4. I tried out all the other flags and they work just fine(if that helps)