Build and Go! Error?

When I build and go, it said that i have a error. It can not find the 3.1.3? So does that mean i have the wrong version of Unity? or the wrong version of the iphone sdk? :?

Hiya…there are a few posts in here about that (search or look around for OS4 build issues)

Short answer: just set the Base SDK to 4.0

EDIT: one of a few related threads: http://forum.unity3d.com/viewtopic.php?t=56873