Why Object may fail to Rez.

I've been told trying to rez an object from your inventory fails becasue of a DataBase issue. This might be true but another cause may be a combination of things. The distance from the camera to the sprims face, and the size you are trying to rez on top of. Also how close to the face center. Next time you get a "Failed to place object at specified location. Please try again." message pull the camera as far back as you can and trying on the same spot. I finding this 100% reproduceable. after spending Three hours just rezzing objects from my inventory I found the above to be the case everytime I get a fail.