mesh error

ok guys so recently i started a complete new project i made some objects in google sketchup and ported them into unity they have mesh collider because ther cannot use other because they are in bell shape i keep getting this error:

Actor::updateMassFromShapes: Compute mesh inertia tensor failed for one of the actor's mesh shapes! Please change mesh geometry or supply a tensor manually! UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag(HierarchyProperty, Boolean) UnityEditor.DockArea:OnGUI()

i know i would actually need to change from mesh collider to box collider or something but i can't so i would just want to "mute" this error if possible so thats why i need your help :)