Well with no code and not knowing what version of NGC you are using it will be hard to help. The only thing I can think of right off is you are scaling the objects with DBP's native scale object command instead of the SetObjScalePRO command in NGC. Also if you are using version 3 make sure all 3 values in every SetObjRadiusPRO command are the same size and turn off the octree system as it is bugged.
Basically with NGC (all versions) you have a certain layout that works with almost any code. It is formatted like this.
delcare constants for making NGC easier to read
turn sync on and set sync rate
start collision system (StartCollisionPRO)
start debug mode (if developing)
if version 3 set exclusive mode for replacement commands (i use 0)
define the constants for your collision types (player, world, etc.)
setup how you want your objects to collide (SetCollisionsPro)
load your objects
set objects to a collision type (CollisionTypePRO)
set your objects size, radius, gravity, rotation and anything else affecting object
start your main loop
move, rotate objects
update the collision system (RunCollisionPRO())
update the camera to players position
use sync to show changes
end your loop
always follow this order and all should be well.
