There are two things about this model that cause concern:
1. It's 5,000 polies and you want NWN to volumetricly shadow it. That's not going to happen or if it does, it's not going to be pretty.
2. It's probably uncompiled.
Compile your tile.
The much easier way to go about this is to turn Render on & Shadows off on the statue but make a fake skeleton for it which has Render turned off but Shadows turned on. And by "fake skeleton" I mean a vastly simplified model which will not choke the volumetric shadow system.
Your model is 5,000 polygons. This model is 188,095 polygons:
The model in the video loads instantly, displays flawlessly and might as well almost be a chest as far as NWN is concerned. It is this way because I do not ask NWN to make volumetric shadows for it and I compile it prior to starting the game.