I am using Excel 2003 (ancient like me). I can insert an entry into the
HPageBreaks collection by "Insert/PageBreak" in Excel or by
ActivePage.HPageBreaks.add befo=Range("A28")
in VBA.

When I use either method, the page break is, in fact in the collection.
However when I look with Print Preview or actually print the worksheet, the
pagebreak does not take place. There is also no page marker in normal
view.

If I select the cell (or row) and click on the Insert menu, one of the
options is "Remove PageBreak" so I know the break is in the collection.

What could be causing this and how can I fix it?

Many thanks for any help.