Cannot rez object on ground

I built a chair and was moving things around so it was in the air, about 3 meters off the ground. I took it into inventory, and when I rezzed it the next time, it rezzed in the air. I moved it to the ground, took it back in inventory, but no matter what I try, I cannot get it to rez back to the ground. There are 10 prims and I unlinked and made sure the root prim was touching the ground. There had been a sitting script in the chair but I removed that as well as the pose but no luck.

What am I doing wrong?

Dmitriy

general grid problems have been known to cause this, try rezzing it in a different sim.
this will also happen if youre trying to rez onto a megaprim.

I think this happens when you have a path cut prim, and if the object is adjusted so that it appears to sit on the ground, you'll have invisible parts of some prims partially underground. How to fix it... it may be feasible to use a script like this to automatically move the object down a bit after rezzing:

default
{
on_rez(integer param)
{
llSetPos(llGetPos() + <0.0, 0.0, -0.5>;
}
}

Thank you for the replies. I tried another sim but that did not work. It might have been the cut prim thing. I tried the script idea that Day Oh had and it worked perfectly. Again, many thanks.