Problems with 1991 tracks

I downloaded the Montreal, Monaco, Barcelona and Interlagos version for the 1991 mod with all the sponsors from that year, but i got a problem that in the readme it says that i must turn off bump mapping to get the realistic asphalt texture, so well when i turn off bump mapping the lines painted on the asphalt keep flickering and dissapearing constantly, for example in Monaco, the pedestrian strips dissapear in front of me and appears again behind, is there some fix for this?

thanks.