I believe that Yossam meant the *object* is not zeroed in the *modeling program* that made it. And therefore it cannot appear correctly positioned in TG.
This is a common mistake that even experienced modelers make, it is easy to forget to do when you are ready to save out the finished object.
Simply open the object in a modeler and move the objects pivet point to its center, and then make sure the object is at 000 in the modeler, and then re-save.
Actually, the base of the object should only be a little below the 0 in the Y. otherwise the object will be half in the ground.
Posting your TGD does not help. You must post the objet for us to test. If you do not have a modeler, post the .obj and associated files, and I will fix it for you... *Assuming that the above is indeed the real issue.*
Cheers.