upgrading to v2.1

problems with upgrading to v 2.1,executed upgrade sql v2.1 over database with following result and dont know solution, anyone?

--Add one more column to [ExternalAuthenticationRecord] table
IF NOT EXISTS (SELECT 1 FROM syscolumns WHERE id=object_id('[dbo].[ExternalAuthenticationRecord]') and NAME='Email')
BEGIN
ALTER TABLE [dbo].[ExternalAuthenticationRecord]
ADD [Email] nvarchar(MAX) NULL
END
Msg 2705, Level 16, State 4, Line number 4
Column names in each table must be unique. Column name 'Email' in table 'dbo.ExternalAuthenticationRecord' is specified more than once.

--SEO friendly language URLs
IF NOT EXISTS (SELECT 1 FROM syscolumns WHERE id=object_id('[dbo].[Language]') and NAME='UniqueSeoCode')
BEGIN
ALTER TABLE [dbo].[Language]
ADD [UniqueSeoCode] [nvarchar](2) NULL
END
Msg 2705, Level 16, State 4, Line number 4
Column names in each table must be unique. Column name 'UniqueSeoCode' in table 'dbo.Language' is specified more than once.

--Allow store owner to disable "Add to wishlist" button for a certain product variant
IF NOT EXISTS (SELECT 1 FROM syscolumns WHERE id=object_id('[dbo].[ProductVariant]') and NAME='DisableWishlistButton')
BEGIN
ALTER TABLE [dbo].[ProductVariant]
ADD [DisableWishlistButton] [bit] NULL

EXEC ('UPDATE [dbo].[ProductVariant] SET [DisableWishlistButton] = [DisableBuyButton]')

ALTER TABLE [dbo].[ProductVariant] ALTER COLUMN [DisableWishlistButton] [bit] NOT NULL
END
Msg 2705, Level 16, State 4, Line number 4
Column names in each table must be unique. Column name 'DisableWishlistButton' in table 'dbo.ProductVariant' is specified more than once.

IF NOT EXISTS (SELECT 1 FROM syscolumns WHERE id=object_id('[dbo].[Product]') and NAME='ProductTemplateId')
BEGIN
ALTER TABLE [dbo].[Product]
ADD [ProductTemplateId] int NULL
END
Msg 2705, Level 16, State 4, Line number 3
Column names in each table must be unique. Column name 'ProductTemplateId' in table 'dbo.Product' is specified more than once.