Hi Gerard.
I really don't know what could be, but it looks like you are having issues with a custom property, right?
Have you defined its Descriptors?
Protected Overrides Function GetCustomBindablePropertyDescriptors() As MicroFour.StrataFrame.Business.FieldPropertyDescriptor()
'-- Return the array of property descriptors
Return New MicroFour.StrataFrame.Business.FieldPropertyDescriptor() { _
New ReflectionPropertyDescriptor("custom_1", GetType(MyBO)), _
New ReflectionPropertyDescriptor("custom_2", GetType(MyBO))}
End Function