Stick this code in your web page:
<style type="text/css">
/* <![CDATA[ */
#obmessage table, #obmessage td
{
border-width: 1px 1px 1px 1px;
border-spacing: 0;
margin:0;
border-collapse: collapse;
}
/* ]]> */
</style>
or just
<style type="text/css">
TABLE {border-collapse:collapse}
</style>
and enter your lotus notes web table as before.