Could not convert variant of type / blahdieblahdieblah (Dispatch) into type / blahdieblahd string

procedure TCoPDBSearch.DoShow;
var
  Sheet_name : string;
    i, r, c,x,y ,last_column, last_row :integer;
 sheet: variant;
 Iedt: IaxpEdit;
  frmSearch: TfrmSearch;
begin
  frmSearch := TfrmSearch.CreateEx(Self, PDBAddinVer);
  try
     for i:= 1 to HostApp.ActiveWorkbook.WorkSheets.Count do
  begin 
    Sheet_name := Hostapp.ActiveWorkbook.WorkSheets[i].Name;
     Sheet := hostapp.Worksheets.Item[Sheet_name];
     Sheet.Activate;
     Sheet.Cells.SpecialCells(xlCellTypeLastCell,EmptyParam).Activate;
     Last_column := hostapp.ActiveCell.Column;
     Last_row := hostapp.ActiveCell.Row;
     r := 0;
     repeat
        inc(r);
        c := 0;
        repeat
           inc(c);
            IEdt := FindControl(EdtSearchTag, axpEdit) as IaxpEdit;
            if pos(iedt.Text,hostapp.Cells.Item[r,c]) > 0
           then
           // add item to a memo for export
            frmSearch.mmo1.Lines.Add(Trim(hostapp.Cells.Item[r,c].Value));
 until c = Last_column;
     until r = Last_row;
  With frmSearch.mmo1 do
  for x := Lines.Count-1 Downto 0 Do
  for y := Lines.Count-1 Downto 0 Do
if (x <> y) Then If Uppercase(Trim(Lines[x])) = Uppercase(Trim(Lines[y])) Then
 begin
   Lines.Delete(x);
   continue; // it is necessary to break the inner loop once the line is deleted
 end;
  end;
  frmSearch.stat1.Panels[0].Text := PDBSW;
  frmSearch.edtPath.Text := GetShortPath(GetModuleName(hInstance),15);
   frmSearch.stat1.Panels[2].Text := IntToStr(frmSearch.mmo1.Lines.count)+' item(s) found';
   frmSearch.ShowModal;
  finally
    frmSearch.Free;
  end;
end;