Passing param to linkbutton

[WorkGoddammit]

Hi, I want to create a datagrid with an extra column
containing a linkbutton. Clicking on the linkbutton
invokes a function and passes a parameter containing the
id of the row in question. I've been struggling with this
for a while now. Any help would be really appreciated!
See the code below.
The error I get is "The best overloaded method match for
OnDelete(long)' has some invalid arguments"
IN HTML:
<asp:datagrid id="grid" AutoGenerateColumns="False"
Runat="server">
<Columns>
<asp:BoundColumn DataField="UserName"
HeaderText="Name"></asp:BoundColumn>
<asp:templatecolumn>
<headertemplate>Delete Option</headertemplate>
<itemtemplate>
<asp:LinkButton id="lbtnDelete" Text="Delete"
OnCommand="CommandBtn_Click" CommandName="Id"
CommandArgument="<%# DataBinder.Eval
(Container.DataItem, "Id") %>" runat="server" />
</itemtemplate>
</asp:templatecolumn>
</Columns>

SCRIPT IN HEADER
<script language="C#" runat="server">
void CommandBtn_Click(object sender,CommandEventArgs e)
{
OnDelete(e.CommandArgument);
}
</script>
CODEBEHIND:
public void OnDelete(long id)
{
Delete(id);
}