Page content duplicated in shared borders

When I publish my website using FP2003 the borders (top and bottom) display
the page content rather than the border content (so that the page content
appears 3 times on the page).

After extensive experimentation I have discovered that the problem depends
upon the size of the original border HTML files (as held within the _borders
folder within FrontPage).

If the border file is 256 bytes or less then there is no problem - the
border displays correctly when published.

If, however, the border file is more than 256 bytes (even by a single
character) then the border contains the page content when published.

You can see this demonstrated at
http://s198740865.websitehome.co.uk/test.htm

The top and bottom border files are identical, except that the bottom border
file has one extra character added to the border content. The top border
displays correctly; the bottom border does not.

Before discovering the above I had pointed my hosting provder in the
direction of the following KB article about shared borders being displayed
incorrectly on UNIX servers:

http://support.microsoft.com/default.aspx?scid=kb;en-us;Q299 360

Their response was that the use FPE 5.0 and so this did not apply.

I would be very grateful if someone could suggest a resolution to this
problem. Many thanks.