JavaScript Error In IE6 When Opening ASPxGridView Edit Form

I'm using DevExpress ASPxGridView edit form, using default edit form. However when I open the edit form in IE6 and click "update" to insert the record, it causes a JavaScript error that says "type" is null or not an object". However it works fine in IE7. I am puzzled and unsure of how to resolve this. Code is below.

<dx:ASPxGridView ID="ASPxGridView_JobTitles" runat="server"
AutoGenerateColumns="False" Caption="Titles"
ClientInstanceName="ASPxClientGridView_Titles"
DataSourceID="SqlDataSource_JobTitle" KeyFieldName="Title" Width="500px">
<Settings UseFixedTableLayout="True" />
<Columns>
<dx:GridViewCommandColumn ButtonType="Image" Caption=" " VisibleIndex="0"
Width="65px">
<UpdateButton Visible="True">
<Image Url="~/images/update.png">
</Image>
</UpdateButton>
<CancelButton Visible="True">
<Image Url="~/images/cancel.png">
</Image>
</CancelButton>
<EditButton>
<Image Url="~/images/file_edit.png">
</Image>
</EditButton>
<HeaderTemplate>
<dx:ASPxButton ID="ASPxButton_New0" runat="server" AutoPostBack="false"
Image-Url="~/images/file_add.png" Text="New">
<ClientSideEvents Click="function(s,e){ASPxClientGridView_Titles.AddNewRow();}" />
</dx:ASPxButton>
</HeaderTemplate>
</dx:GridViewCommandColumn>
<dx:GridViewDataTextColumn FieldName="Title" VisibleIndex="1">
<PropertiesTextEdit>
<ValidationSettings CausesValidation="True">
<RequiredField ErrorText="Is Required" IsRequired="True" />
</ValidationSettings>
</PropertiesTextEdit>
</dx:GridViewDataTextColumn>
<dx:GridViewCommandColumn ButtonType="Image" Caption=" " VisibleIndex="2"
Width="65px">
<DeleteButton Visible="True">
<Image Url="~/images/file_delete.png">
</Image>
</DeleteButton>
</dx:GridViewCommandColumn>
</Columns>
<SettingsBehavior ConfirmDelete="True" />
</dx:ASPxGridView>
<asp:SqlDataSource ID="SqlDataSource_Title" runat="server"
ConnectionString="<%$ ConnectionStrings:TEST %>"
SelectCommand="SELECT [Title] FROM [Titles]"
UpdateCommand="UPDATE Titles SET Title = @Title WHERE (Title = Title)"
DeleteCommand="DELETE FROM Titles WHERE (Title = @Title)"
InsertCommand="INSERT INTO Titles(Title) VALUES (@Title)">
<InsertParameters>
<asp:Parameter Name="Title" Type="String" />
</InsertParameters>
<UpdateParameters>
<asp:Parameter Name="Title" Type="String" />
</UpdateParameters>
</asp:SqlDataSource>