Collisions.. again :(

hmm.. It seems there are a lot of collision questions on the board. I thought that I was doing well with them until just recently, I've hit a stumbling block (heh.. surprise). Here's what's going on. My 'Terrain to Bullet' collisions work great, my 'Bullet to Player' Collisions work fine, my 'Player to Player' collisions are fine. BUT.... I tried to put powerups in my game (simple rotating textured cubes that the player can run into to get health/armor/goodies etc..), and it's not running my collision code. I'm getting the sliding effect, but if you look at my implementation code at the bottom, it's not hitting the stop I put in place, nor is it hiding the power-up after the collision. My player just slides around the powerup, with no action happening in the code.

Here's what I've got:

Here's my initial declarations:

; Collision Types
Const Terrain_Col 	= 1
Const Bullet_Col 	= 2
Const Rider_Col		= 3
Const Ostrich_Col	= 4
Const PowerUP_Col	= 5

... and here's my initialization for the collisions:

Collisions Bullet_Col, Terrain_Col, 2, 1
Collisions Bullet_Col, Rider_Col, 2, 1
Collisions Bullet_Col, Ostrich_Col, 1, 1
Collisions Ostrich_Col, Ostrich_Col, 1, 2
Collisions Ostrich_Col, PowerUP_Col, 1, 2

.. My PowerUp creation code:

Function SpawnPowerUp(PType,x#=0,y#=0,z#=0, rp = 20000)
	PowerUp.T_PowerUp = New T_Powerup
	Powerup\xPos# = x#
	Powerup\yPos# = y#
	Powerup\zPos# = z#
	
	PowerUp\Respawn = TimeKeeper + rp
	PowerUp\Active = 1
	
	If PowerUP\yPos# = 0 Then PowerUp\yPos# = TerrainY(Terrain\ObjectHandle, x#, y#, z#)
	
	Select PType
		Case HEALTH
			PowerUP\ObjectHandle = CopyMesh(HealthCrate)
			EntityType PowerUP\ObjectHandle, PowerUP_COL
			ShowEntity PowerUp\ObjectHandle
	End Select
	size# = 1.2
	modelheight# = MeshHeight(PowerUP\ObjectHandle)
	ScaleEntity PowerUP\ObjectHandle, (1.0/modelheight#) * size#, (1.0/modelheight#) * size#, (1.0/modelheight#) * size#
	;EntityBox PowerUP\ObjectHandle, PowerUp\xPos#, PowerUp\yPos#, PowerUp\zPos#, 1.2, 1.2, 1.2
	EntityRadius PowerUP\ObjectHandle, 1.0
	PositionEntity PowerUP\ObjectHandle, PowerUp\xPos#, PowerUp\yPos#, PowerUp\zPos#
	
End Function

... and here's my implementation:

; _Update Powerups
		For PowerUP.T_PowerUP = Each T_powerup
			TurnEntity PowerUp\ObjectHandle, 0,0.7,0
			
			If EntityCollided(PowerUp\ObjectHandle, Ostrich_COL) Then
				Stop
				HideEntity PowerUp\ObjectHandle
			EndIf
		Next

Bother the Player and the PowerUP have their entity radius set. I've tried EntityBox and Polygon Collisions, and nothing is working. I at least get the stop/sliding effect with Sphere2Sphere collision, but it still won't trigger my code. After looking at this for a week, I think I'm probably overlooking something simple and obvious, but can't for the life of me find it. Any thoughts?