Datagrid Databind "System.FormatE xception: Input string was not in a correct format"

[bnlockwood]

G'day all,

Thank you in advance for anyone that can help.

I have a shopping cart datagrid on my c# asp.net page.
This is the code:

-------------------------------------

<asp:datagrid id="grdShopping Cart" OnItemDataBound ="ItemDB"
ShowFooter="Tru e" AutoGenerateCol umns="False" Runat="server"
BorderStyle="No ne" Width="788px" GridLines="None ">
<ItemStyle Font-Size="X-Small" Height="50px"
BackColor="Whit e"></ItemStyle>
<HeaderStyle Font-Size="X-Small" Font-Names="Arial" Height="35px"
ForeColor="Whit e" BackColor="DimG ray"></HeaderStyle>

<Columns>
<asp:TemplateCo lumn HeaderText="Bas e Part#">
<ItemTemplate >
<asp:Label Runat="server" ID="Product"><% #DataBinder.Eva l(Container,
"DataItem.produ ct_nm")%></asp:Label>
</ItemTemplate>
</asp:TemplateCol umn>
<asp:BoundColum n DataField="cart _product_unit_c ost" HeaderText="Uni t
Cost" DataFormatStrin g="{0:C}"></asp:BoundColumn >
<asp:TemplateCo lumn HeaderText="Qty ">
<ItemTemplate >
<asp:TextBox Width="90px" Runat=server
Text='<%#DataBi nder.Eval(Conta iner, "DataItem.cart_ product_qty")%> '
ID="Quantity" /> </ItemTemplate>
</asp:TemplateCol umn>
<asp:BoundColum n DataField="cart _product_total_ cost" HeaderText="Uni t
Total Cost"></asp:BoundColumn >
</Columns>
</asp:datagrid>

------------------------------------- << This works

But when I try to add another column like

<asp:TemplateCo lumn HeaderText="Des cription">
<ItemTemplate >
<asp:TextBox Runat=server Text='<%#DataBi nder.Eval(Conta iner,
"DataItem.produ ct_desc")%>' ID="Description " /> </ItemTemplate>
</asp:TemplateCol umn>

it errors with a System.FormatEx ception: Input string was not in a
correct format.
I've even tried entering a simple.

<asp:TemplateCo lumn HeaderText="Des cription">
<ItemTemplate >
<asp:TextBox Runat=server Text='This is a description'
ID="Description " /> </ItemTemplate>
</asp:TemplateCol umn>

Can anyone enlighten me as to what I'm doing wrong? I guess I can rule
out any database stuff because even if I type the static description it
errors as well.

Any advice or help would really be appreciated.
Kind regards,
Brian