Usually a problem like this occurs when you set the size of something like a door frame or a panel size to 0.
If you cannot figure out what the problematic parameter is, the way to re-set an object to its defaults is to:
1) select the object
2) open its Settings Menu
3) select any other object in the left-hand Object Selector side of the menu.
4) select your original object in the Selector.
Hopefully one of these helps
Tom Waltz