Looking at that rocket, I think you\'re losing stability in the connectors (or lack thereof) between outer and inner tanks. As a result, the tanks will swing back and forth during takeoff, and this swiniging action will cause the rocket to tip over from uneven thrust. The way to stop this from happening is to attach connectors to the layers of boosters in a ring-like fashion, where all the outer boosters are linked by connectors. That, and in weak places, like near stage decouplers, having vertical connectors will help you too. The big idea is to prevent as much from swinging as possible. After that, I see a lot of SRBs on that thing. For whatever reason, SRBs don\'t like to go straight. You compensate by adding a few SAS modules on that part of your rocket.