"Deleted row information cannot be accessed through the row." WHY!!

[gamerPotatoe]

hi guys, I have a problem with my datagrid. My form is set up so I have two textboxes an add button and an editable datagrid. The datagrid is bound to a datatable which is in my cache.When I click the add button the contents of the textboxes are insertedinto the datatabel in teh cache and the datagrid is bound to it. However the problem comes when I delete a row from the database and then add and edit a row. Lets say my datagrid has only one row, I delete it and then insert a new row. WHen I click on the Edit button I get the following error Deleted row information cannot be accessed through the row. Heres my code for the editable datagrid Private Sub dgEditEducation_ItemCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles dgEditEducation.ItemCommand Select Case e.CommandName Case "Update" populateEducationQ() tblEducation = Cache.Get("tblEducation") Dim dr As DataRow 'find the row which has been clicked on dr = tblEducation.Rows.Item(e.Item.ItemIndex) '.Find(CType(E.Item.FindControl("lblEduID2"), Label).Text) dr.BeginEdit() dr("institute") = CType(e.Item.FindControl("txtEdEInstitute"), TextBox).Text dr("location") = CType(e.Item.FindControl("txtEdELocation"), TextBox).Text dr("eYear") = CType(e.Item.FindControl("ddEdEYar"), DropDownList).SelectedItem.Text dr("major") = CType(e.Item.FindControl("txtEdEMajor"), TextBox).Text dr("eType") = "q" dr.EndEdit() Cache.Insert("tblEducation", tblEducation) dgEditEducation.EditItemIndex = -1 BindEducationQ() Case "Edit" dgEditEducation.EditItemIndex = e.Item.ItemIndex BindEducationQ() Dim dr As DataRow tblEducation = Cache.Get("tblEducation") dr = tblEducation.Rows(e.Item.ItemIndex) Dim ddl As DropDownList = CType(dgEditEducation.Items(dgEditEducation.EditItemIndex).FindControl("ddEdEYar"), DropDownList) ddl.SelectedIndex = ddl.Items.IndexOf(ddl.Items.FindByValue((dr("eYear")))) Case "Cancel" dgEditEducation.EditItemIndex = -1 BindEducationQ() Case "Delete" tblEducation = Cache.Get("tblEducation")