Jay K. Supertramp

I can't use the main stage because the fuel is a mono fuel tank, LH only without the oxidante. why? in can't understand the problem. screenshot here

thanks a lot! I solved the warning just like that!

I can't solve this warning... b9PartSwitch - Serious Warning b9PartSwitch has encountered a serious warning. The game will continue to run but this should be fixed ASAP. Duplicated subtype names found on ModuleB9PartSwitch (moduleID='textureSwitchPaint on part: Blue, White, White (Alt), White (Topaz) Please see KSP's log for additional details screenshot here