>xl.activesheet.Hyperlinks.Add ("a1","","Sheet1!A20")
I don't have Excel 2000, so I don't know what your second parameter is, but I saw your error as well.
Change your line above to read:
xl.activesheet.hyperlinks.add(x1.activesheet.range("a1"), "Sheet1!A20")
HTH,
Marty
Marty Smith, CSQE