Importing b3d format

here's the code:

Graphics3D 800, 600
SetBuffer BackBuffer()

Const type_sphere = 1
Const type_cube = 2

camera = CreateCamera()
CameraViewport camera, 0, 0, 800, 600
PositionEntity camera, -50, 50, -100

light = CreateLight()

sphere = LoadMesh("sphere.b3d")
EntityType sphere, type_sphere

cube = LoadMesh("cube.b3d")
EntityType cube, type_cube

Collisions type_sphere, type_cube, 3, 1

While Not KeyHit(1)

; key "w"
If KeyDown(17) Then
MoveEntity sphere, 0, 2, 0
EndIf

; key "s"
If KeyDown(31) Then
MoveEntity sphere, 0, -2, 0
EndIf

; key "a"
If KeyDown(30) Then
MoveEntity sphere, -2, 0, 0
EndIf

; key "d"
If KeyDown(32) Then
MoveEntity sphere, 2, 0, 0
EndIf

UpdateWorld
RenderWorld

Flip

Wend
End

But when I run the program, it says entity does not exists. As for exporting b3d in 3ds max, I keep the default settings.