An entity with this key already exists

   Good day,

I've the following code:

Role role;
foreach (var department in departments)
{
    role = new Role();
    role.Name = department;

    em.AddEntity(role);
}

em.SaveChanges();

Which
 used to work fine. But when I cleaned up the db and executed this same 
code, I'm now getting the following error when adding the 2nd entity to 
AddEntity():

"An entity with this key: Role: 0 already exists in this EntityManager"

The
 Id is Primary Key and Identity auto-incremented by 1. But somehow the 
Id is not longer auto-incremented when being added to the EntityManager.

This is the data property of the RoleId, generated by DevForce:

    [Key]
    [DataMember]
    [Bindable(true, BindingDirection.TwoWay)]
    [Editable(true)]
    [Display(Name="Id", AutoGenerateField=true)]
    [IbVal.RequiredValueVerifier( ErrorMessageResourceName="Role_Id")]

And the script for the Role table:

CREATE TABLE [dbo].[Role](
    [Id] [smallint] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](25) NOT NULL,
 CONSTRAINT [PK_Role] PRIMARY KEY CLUSTERED 
(
    [Id] ASC
)WITH
 (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, 
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

Could someone be so kind to point me out what is the problem?

Thanks in advance,
Dave