Error when deleting row in Gridview using GridViewDeleteEventArgs when field is GUID

I've created a gridview listing various documents that have been uploaded to a documents folder on the server.  I have a delete button at the end of the gridview.  When I delete the row I want to delete the associated document.  In order to do this i am using the Gridview Rowdeleteing event: Below is as far as I have gotten in trying to identify the filename from the gridview:

Sub gvdoclist_RowDeleting(ByVal sender As Object, ByVal e As GridViewDeleteEventArgs)

        ' Get the file name of the file being deleted.

        Dim row As GridViewRow = gvDoclist.Rows(e.RowIndex)
        Dim FileNameId As String = row.Cells(2).Text
    End Sub

The stored file name is a GUID that matches the file name in my document folder.  When I click delete I get the following error:

System.InvalidCastException was unhandled by user code
  Message="Unable to cast object of type 'System.Guid' to type 'System.Web.UI.WebControls.GridViewRow'."
  Source="App_Web_kj42myet"
  StackTrace:
       at AdminDocs.gvdoclist_RowDeleting(Object sender, GridViewDeleteEventArgs e) in N:\SmallBusiness\MemberPages\AdminDocs.aspx.vb:line 547
       at System.Web.UI.WebControls.GridView.OnRowDeleting(GridViewDeleteEventArgs e)
       at System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow row, Int32 rowIndex)
       at System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup)
       at System.Web.UI.WebControls.GridView.OnBubbleEvent(Object source, EventArgs e)
       at System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args)
       at System.Web.UI.WebControls.GridViewRow.OnBubbleEvent(Object source, EventArgs e)
       at System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args)
       at System.Web.UI.WebControls.LinkButton.OnCommand(CommandEventArgs e)
       at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
       at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

It seems the system has an issue with the file value being a guid.  Any suggestions on how to capture the file name from the gridview row being deleted?  

Thanks in advance.

Ira