You must have been working in standard view. If you are using tables for a layout like this its best to use layout view as it doesnt put the borders on tables unless thats what you were going for. try this code here and tell me how it goes:

HTML Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body>
<div align="center">
<table width="641" border="0" cellpadding="0" cellspacing="0">
<!--DWLayoutTable-->
<tr>
<td height="6" colspan="3" valign="top"><img src="kaderboven.gif" width="443" height="6"></td>
<td width="197" rowspan="2" valign="top"><img src="bglogin.gif" width="197" height="95"></td>
<td width="1"></td>
</tr>
<tr>
<td width="10" rowspan="3" valign="top"><img src="kaderlinks.gif" width="10" height="371"></td>
<td background="bgcontent.gif" width="429" rowspan="3" valign="top"><!--DWLayoutEmptyCell--> </td>
<td width="4" rowspan="3" valign="top"><img src="kaderrechts.gif" width="4" height="371"></td>
<td height="89"></td>
</tr>
<tr>
<td height="162" valign="top"><img src="bgkal.gif" width="197" height="162"></td>
<td></td>
</tr>
<tr>
<td rowspan="2" valign="top"><img src="bgcorn.gif" width="197" height="125"></td>
<td height="120"></td>
</tr>
<tr>
<td height="5" colspan="3" valign="top"><img src="" width="443" height="5" alt=""></td>
<td></td>
</tr>
</table>
</div>
</body>
</html>
Bookmarks