>What problem does it cause in the Business Layer Generator?

With dbo.MyTable and history.MyTable in the db,

The "Get Data" button causes:

Error: Add-in Exception

Message: Item has already been added. Key in dictionary: 'MyTable' Key being added: 'MyTable'

Source: mscorlib

Stack Trace:
at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
at Collections.Hashtable.Add(Object key, Object value)
at MMBusinessLayerGenerator.mmWizardPageSelectData.ProcessDBCObjects(...)
...

To get around this I created a MyProjectDev user that only has access to the dbo tables. Nice of you to allow editing the connection string in the wizard.