Thread: Run-Time Error '1004'

I am trying to figure out why I get the above error at times when using the range method. The simplest I can get is the following code:

Private Sub CommandButton1_Click()
  Worksheets("Sheet2").Range("A1").Activate
End Sub

If the button in question is on Sheet1, I get the following error:

Run-time error '1004':

Activate method of Range class failed

Can anyone explain what causes the error to pop up?

Thanks!