Typonese is causing your issue (look for the bolding):

-- #3 Table ------------------------------------------------------------------#3 Table

/****** Object: Table [dbo].[Orders] ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE TABLE [dbo].[Orders](

[OrderID] [Int] IDENTITY(1,1) NOT NULL,

[CustomerID] [int] NOT NULL,

[OrderNumber] [nvarchar] (50) NULL,

[OrderDate] [datetime] NULL,

CONSTRAINT [PK_Item] PRIMARY KEY CLUSTERED

(

[OrderID] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,

ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

GO

SET IDENTITY_INSERT [dbo].[Orders] ON

INSERT [dbo].[Orders] ([OrderID], [CustomerID], [OrderNumber], [Orderdate])

VALUES (1, 1, N'10001', '6/15/2011')

INSERT [dbo].[Orders] ([OrderID], [CustomerID], [OrderNumber], [Orderdate])

VALUES (2, 2, N'10002', '6/16/2011')

INSERT [dbo].[Orders] ([OrderID], [CustomerID], [OrderNumber], [Orderdate])

VALUES (3, 1, N'10003', '6/17/2011')

INSERT [dbo].[Orders] ([OrderID], [CustomerID], [OrderNumber], [Orderdate])

VALUES (4, 2, N'10004', '6/18/2011')

SET INDENTITY_INSERT [dbo].[Orders] OFF

Correct the spelling of IDENTITY and the rest should work.