Delete a Row in Gridview causing a problem

Here it is
protected void ContactsGridView_RowCommand(object sender, GridViewCommandEventArgs e)
{

// If multiple buttons are used in a GridView control, use the
// CommandName property to determine which button was clicked.
if (e.CommandName == "Load Account")
{
// Convert the row index stored in the CommandArgument
// property to an Integer.
int index = Convert.ToInt32(e.CommandArgument);

// Retrieve the row that contains the button clicked
// by the user from the Rows collection.
GridViewRow row = ContactsGridView.Rows[index];

// Create a new ListItem object for the contact in the row.
ListItem item = new ListItem();
item.Text = Server.HtmlDecode(row.Cells[1].Text);

// If the contact is not already in the ListBox, add the ListItem
// object to the Items collection of the ListBox control.
if (!ContactsListBox.Items.Contains(item))
{
ContactsListBox.Items.Add(item);
}

ContactsGridView.DeleteRow(row.RowIndex);
}