if you dont do Zero's mission and you have completed all the other peoples mission's then you are going to have to complete the zero mission (supply line) or you can just not play GTA San andreas ever again that is what i had to do i had to complete his mission after i did everyone else's mission so yeah it took me like 2 days to complete that mission but after that mission will come the (new model army) mission and here's heads up, to comeplete the (new model army) mission use your left mouse button to pick up the objects and then click left again to drop after you got it out of the way and when it comes to the bomb part you do the same thing (use left mouse button to pick up and then click left mouse button again to drop once it is out of the way and when it comes to the part with the bridge go over to your camp and then use your LMB (left mouse button) to pick up the bridge and then go over to the part where you have to put the bridge and then click LMB again to drop it and all ok well i hoped this helped and bye!!!!!!!!!!!!! :) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :)