OK I found the solution :
In the index.php and single.php at the end of both files:
Replace this:
`<br style=”clear:both” /><!– without this little
NS6 and IE5PC do not stretch the frame div down to encopass the content DIVs –>
</div>
<!– footer –>
<?php get_footer(); ?>
<? ob_end_flush();?>`
By this:
<br style=”clear:both” /><!– without this little
NS6 and IE5PC do not stretch the frame div down to encopass the content DIVs –>
<!– footer –>
<?php get_footer(); ?>
</div>
<? ob_end_flush();?>
=)