Other than a logic error resulting in an endless loop, the most frequent cause of stack overflow exceptions seems to be accidentally referencing what should be the name of a member variable in a Property get/set with the name of the property and not the name of the member variable.  This is most common in case-sensative languages such as C# where lower case is often used for the member variable and camel case for the property name.  It can also happen in VB as follows where Name rather than mName has been used in either the Get or Set or both:

Private mName As String

Public Property Name As String
    Get
       Return Name
    End Get
    Set (ByVal Value As String)
       Name=Value
    End Set
End Property

So, I'd begin by checking the all the property declarations of the business object class.