Why do I get error when I try to insert a XML docment with date element into SQL 2005 database?

When I the following XML with date element into database, I get the error information below, why?

.Net SqlClient Data Provider: Msg 6926, Level 16, State 1, Line 2
XML Validation: Invalid simple type value: '2005-12-23'. Location: /*:Folder[1]/*:Bookmark[1]/*:InputDate[1]

//----------XSD for Bookmark field-------------
CREATE XML SCHEMA COLLECTION [dbo].[mycollect]
AS N'

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:element name="Folder" type="folderType"/>

<xsd:complexType name="bookmarkType">
<xsd:sequence>
<xsd:element name="Title" type="xsd:string" />
<xsd:element name="Url" type="xsd:string" />
<xsd:element name="Description" type="xsd:string" />
<xsd:element name="InputDate" type="xsd:date" />
<xsd:element name="IsPrivate" type="xsd:boolean" />
</xsd:sequence>

<xsd:attribute name="BId" type="xsd:string" />

</xsd:complexType>

<xsd:complexType name="folderType">

<xsd:all>
<xsd:element name="Folder" type="folderType" minOccurs="0" />
<xsd:element name="Bookmark" type="bookmarkType" minOccurs="0" />
</xsd:all>

<xsd:attribute name="Name" type="xsd:string" />
<xsd:attribute name="Id" type="xsd:string" />

</xsd:complexType>

</xsd:schema>

'
GO

//----------XSD for Bookmark field--------------

//----------Insert XML with date element into database---------

INSERT INTO cw_Bookmark (UserID,Bookmark) VALUES ('b50cf8fe-749c-4e38-ab2f-6d0ui9711brt',
'
<Folder Name="Root" Id="a6dce8fe-749c-4e38-ab2f-3d03d9711b3d">

<Bookmark BId="f8dce8hj-846c-4e38-ab2f-6d03d9711b80">
<Title>CodeGuru Forums - ASP.NET</Title>
<Url>http://www.codeguru.com/</Url>
<Description>This is a good site</Description>
<InputDate>2005-12-23</InputDate>
<IsPrivate>false</IsPrivate>
</Bookmark>

<Folder Name="Card1" Id="b8dcf8fe-749c-4e38-ab2f-6d03d9711b8j">

<Bookmark BId="fkdfh3a8-456c-6y38-jk2f-5h0gh9711b45">
<Title>Keystone DreamCard</Title>
<Url>https://www.mydreamcardonline.com</Url>
<Description>Please note</Description>
<InputDate>2004-09-25</InputDate>
<IsPrivate>true</IsPrivate>
</Bookmark>

<Folder Name="Card1in1" Id="l9dcf8fe-689c-0935-fghj-7u03d9711b5t">
<Bookmark BId="ghdfh3a8-896c-6y40-jkfg-5h0gh9711b89">
<Title>The News of CNN</Title>
<Url>https://www.cnn.com</Url>
<Description>Please note</Description>
<InputDate>2004-09-23</InputDate>
<IsPrivate>True</IsPrivate>
</Bookmark>
</Folder>

</Folder>

</Folder>

')

//----------Insert XML with date element into database---------