The field you are binding to does not have a field property descriptor associated with it which is generally created through the BO Mapper.  I assume you created a custom property and then attempted to bind to that property.  This can be done, but requires a field property descriptor to prevent .NET from using reflection during the binding process.

In the business object 'ChkSourceBO' you will need to add the following code:

Imports
Imports MicroFour.StrataFrame.Business
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports MicroFour.StrataFrame.UI.Windows.Forms

Code Overrides in the ChkSourceBO.vb file
Protected Overrides Function GetCustomBindablePropertyDescriptors() _
     As MicroFour.StrataFrame.Business.FieldPropertyDescriptor()
        Return New FieldPropertyDescriptor() _
         {New ReflectionPropertyDescriptor("3", GetType(ChkSourceBO))}
End Function

There is additional information on this in the help documentation.  You can locate the article at:

Contents -> Business Layer -> Adding Custom Field Properties

Hope this helps.

P.S. This should have nothing to do with the DevExpress textbox and should behave the same way with a standard SF textbox.

An error occurred while refreshing the data from field 'ChkSourceBO.3' to property 'Text' on control 'fldIncrement.'  Are you missing FieldPropertyDescriptor for a custom property?

I figure this is some kind of conversion or formatting thing trying to go from an integer to a string.  Am I missing anything here?  Why is my field showing as ChkSourceBO.3 when the field is ChkSourceBO.FloatIncr?  The value it's trying to populate is 3...not sure what that's about.  Any ideas?