Problem with subdivision surface and multires

Why does subdivision surface and multires do this to my object? And what should I do to fix the problem?
I am brand new to 3D modeling and Blender, and this is my first try!




Thanks!

It looks from your screenshot that the top of the object is one face. You should use quads if you are using subsrf modifier, also have the quads follow the curves of the object and watch for vertices connected to more than 4 edges, this can create visual artifacts if on a curved surface
You should model with the knowledge you are going to use a subsurf modifier rather than just slap it on to any mesh and expect it will magically be wonderful.

You can also look at added a crease weight to selected faces. http://wiki.blender.org/index.php/Doc:2.6/Manual/Modifiers/Generate/Subsurf#Weighted_Creases