Hello,
Did you read my post on getting help? Most of the points in that post apply to your problem. In particular, you need to tell us in detail about every single thing that you have connected and consider removing each component to see if the problem goes away. You also need to tell us what the problem actually is. What happens with it does not work? Does behave better with the motors removed?
It is great that you show working and non-working code, but you could reveal more about the problem by making these two programs much simpler. For example, can you write a program that does not do anything with buttons, but just sets the motor speed to 100? Then make a non-working one that is exactly the same but with the speed set to 101?
Based on your description so far, I am guessing that your motors are just taking more current than what either your batteries or the SVP can provide, but it is hard to be sure.
-Paul