I have a problem that occurs with MS Excel 2003 Professional but not MS Excel 2000 Professional. I am on Windows XP.

The Macro runs without an error message, but instead of completing, it seems to be stuck in a loop where it keeps forcing blank lines to print.
The piece of code causing the problem is below:

Set myRange = ActiveSheet.UsedRange
For Each rw In myRange.Rows

If insertNextRow Then
Rows(rw.Row).Select
Selection.Insert Shift:=xlDown
End If

insertNextRow = False
If rw.OutlineLevel = 3 Then
insertNextRow = True
End If

Next rw

This part of the macro inserts a row between subtotalled groups only. This works in Excel 2000 but in Excel 2003 it will keep inserting lines forever unless you break out of the macro.

Hmm... It's probably adding the current line to the 'used range' and therefore the next line will always have that indent level, therefore always be true. If that's the case, this should fix it and should work for both:
--------------------------------------------------------------------
Private Sub CommandButton1_Click()

Set myRange = ActiveSheet.UsedRange

For Each rw In myRange.Rows

If insertNextRow Then
  Rows(rw.Row).Select
  Selection.Insert Shift:=xlDown
End If

If rw.OutlineLevel = 3 And Not insertNextRow _
  Then insertNextRow = True _
  Else insertNextRow = False

Next

End Sub
--------------------------------------------------------------------
Hope this works for you