Corrupt South America Default Scenery

Hi All:Somehow I have messed up my South America default scenery betweenS 7* and about S 47* or S 48*. All of the elevations are off. Theairports and lakes are on table tops and the mountains are flat.I only have two addons down there, fireland mesh and Rio scenery,and removing them doesn't help. It's the only corrupt scenery Icould find in the world. I'll have to admit I have added a lotof scenery since the last time I flew down there, so I'm kind oflosted. Any advice would be greatly appreciated.Thanks