sql server constrainst issues while deleting

Products Table: 
USE [shopping]
GO
/****** Object:  Table [MyTests].[Products]    Script Date: 11/07/2009 11:26:45 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
SET ANSI_PADDING ON
GO
CREATE TABLE [MyTests].[Products](
	[ProductID] [int] IDENTITY(1,1) NOT NULL,
	[Code] [nvarchar](25) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[Name] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[ProdDescription] [varchar](max) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[Price] [decimal](18, 0) NULL CONSTRAINT [DF__Products__Price__38996AB5]  DEFAULT ((0)),
	[Cost] [decimal](18, 0) NULL CONSTRAINT [DF__Products__Cost__398D8EEE]  DEFAULT ((0)),
	[Net] [decimal](18, 0) NULL CONSTRAINT [DF__Products__Net__3A81B327]  DEFAULT ((0)),
	[ImageURL1] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[ImageURL2] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[DateAvailable] [datetime] NULL CONSTRAINT [DF__Products__DateAv__3B75D760]  DEFAULT (getdate()),
	[StockQTY] [int] NULL CONSTRAINT [DF__Products__StockQ__3C69FB99]  DEFAULT ((0)),
	[CatID] [int] NULL CONSTRAINT [DF__Products__CatID__3D5E1FD2]  DEFAULT ((0)),
	[SubCatID] [int] NULL CONSTRAINT [DF__Products__SubCat__3E52440B]  DEFAULT ((0)),
	[Status] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[SortOrder] [int] NULL CONSTRAINT [DF__Products__SortOr__3F466844]  DEFAULT ((0)),
	[ShipCost] [decimal](18, 0) NULL CONSTRAINT [DF__Products__ShipCo__403A8C7D]  DEFAULT ((0)),
	[ShipCostMulti] [decimal](18, 0) NULL CONSTRAINT [DF__Products__ShipCo__412EB0B6]  DEFAULT ((0)),
	[Taxable] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
 CONSTRAINT [PK__Products__37A5467C] PRIMARY KEY CLUSTERED 
(
	[ProductID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] 
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [MyTests].[Products]  WITH CHECK ADD  CONSTRAINT [categoriesproducts] FOREIGN KEY([CatID])
REFERENCES [MyTests].[Categories] ([CatID])
ON UPDATE CASCADE
ON DELETE CASCADE
GO
ALTER TABLE [MyTests].[Products] CHECK CONSTRAINT [categoriesproducts] 
 
PRODUCTOPTIONS TABLE: 
 
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [MyTests].[ProductOptions](
	[OptionID] [int] IDENTITY(1,1) NOT NULL,
	[ProductID] [int] NULL DEFAULT ((0)),
	[OptionName] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
	[Active] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
PRIMARY KEY CLUSTERED 
(
	[OptionID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] 
GO
ALTER TABLE [MyTests].[ProductOptions]  WITH CHECK ADD  CONSTRAINT [productsproductoptions] FOREIGN KEY([ProductID])
REFERENCES [MyTests].[Products] ([ProductID])
ON DELETE CASCADE
GO
ALTER TABLE [MyTests].[ProductOptions] CHECK CONSTRAINT [productsproductoptions] 

PRODUCTOPTIONSITEMS TABLE: 
 
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [MyTests].[ProductOptionItems](
	[OptionItemID] [int] IDENTITY(1,1) NOT NULL,
	[OptionID] [int] NULL DEFAULT ((0)),
	[OptionItemPrice] [money] NULL DEFAULT ((0)),
	[ItemDesc] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
PRIMARY KEY CLUSTERED 
(
	[OptionItemID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] 
GO
ALTER TABLE [MyTests].[ProductOptionItems]  WITH CHECK ADD  CONSTRAINT [productoptionsproductoptionitems] FOREIGN KEY([OptionID])
REFERENCES [MyTests].[ProductOptions] ([OptionID])
ON DELETE CASCADE
GO
ALTER TABLE [MyTests].[ProductOptionItems] CHECK CONSTRAINT [productoptionsproductoptionitems]
                                  

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