It's a new object you added or an existing one from gta? If it's new did you add it to an IDE file? Did you wrote that IDE file's directory in gta.dat?
Maybe it's just you're new with MEd.
Try this: Render the desired IPL and click on the green arrow (as shown in the picture) to overview your map. Maybe then you can find your object by zooming in.
Hope that works. This post has been edited by ilir on Saturday, Aug 18 2012, 00:16