From: Ashe1 Writer
x & z numbers were in the positive, but the y number is a negative
Are you talking about position or rotation? If it's position, you must have copied the numbers wrong. There's no such thing as a negative position. All locations within a sim go from <0.0> (the SW corner) to <256,256> (the NE corner).
If it's not obvious, those are the X & Y numbers, by the way. The X axis runs East/West, and the Y axis runs North/South. No location on either axis can be lower than 0, ever.
The Z axis is height, and runs from 0 to infinity. Under normal circumstances though, you can't get above 768 on Z. On the mainland, any number lower than 20 will put you under water, with 0 being the absolute bottom of the ocean floor. Just like with X and Y, you can never go lower than 0 on Z.
In any case, a few things to ask about your house. First, is it all one linkset? If not, then make sure to move all the pieces at once. You won't be able to do that with the numbers; you'll have to do it with the manipulator tool (the arrows). When you type in the number fields, you're only ever affecting the last object selected, not all of them. Only use the numbers if everything is linked or if you want to work on one piece at a time.
One thing that might be happening is that all the pieces of the house are scripted to stay in a certain location relative to some sort of controller object. If that's the case, simply move the controller, and all the other pieces will follow. Most such systems have an option on the controller to clear the scripts, effectively locking the pieces in place and allowing you to delete the controller. (When I say "locked in place", note that I mean the pieces are no longer under the controller's influence. They're not actually locked from editing unless you lock them yourself.)
If your house was packaged with Rez-Foo or Rez Faux, then the packager object is the controller. Touch it, and you'll see a menu pop up with buttons on it. One of the buttons will be called "Freeze" or "Lock" or something to that effect. If it's something else, then it should say so on whatever instruction sheet would have come with the house. Check and see if it came with a notecard.
If the problem is not any of the above, you could be experiencing packet loss. Close SL, check your network connections, restart SL, and try again.
Good luck.