Incollo qui sotto il codice di una tabella che opera correttamente con lo spazio tra celle, padding, bordi. E' la prima riga che definisce la cosa. Nella tua tabella i parametri spazio, padding, bordo sono scritti così?
<table style="width: 505px;" border="0" cellspacing="1" cellpadding="3" bgcolor="#cccccc">
<tbody>
<tr>
<td width="120" bgcolor="#ffffff"></td>
<td width="12" bgcolor="#ffffff"></td>
<td colspan="2" bgcolor="#ffffff">
<div class="Stile1"><span class="Stile3">Banchi
sterili</span></div></td>
<td colspan="3" bgcolor="#ffffff">
<div class="Stile1"><span class="Stile3">Rischio
Biologico</span></div></td>
<td colspan="3" bgcolor="#ffffff">
<div class="Stile1"><span class="Stile3">Rischio
Chimico</span></div></td>
<td colspan="5" bgcolor="#ffffff">
<div class="Stile1"><span class="Stile3">Servizi e
Accessori</span></div></td>
</tr>
<tr>
<td width="120" bgcolor="#ececec">
<p><span class="Stile3 Stile1">Azienda</span></p>
<p>(clicca sul nome)</p></td>
<td width="12" bgcolor="#ececec">
<div class="Stile1">
<p class="Stile3" align="center">T
i
p
o</p>
</div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
F
H</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
F
V</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
B
H</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
F
A</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">G
B
X</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
C
H</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
C
R</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">A
V
S</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">K
S
P</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">P
C
L</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">S
A
T</span></div></td>
<td width="20" bgcolor="#ececec">
<div><span class="Stile3 Stile1">D
P
I</span></div></td>
<td width="20" bgcolor="#ececec">
<div class="Stile3 Stile1">Altro</div></td>
</tr>
<tr>
<td width="120" height="35" valign="middle" bgcolor="#ffffff">
<p><a href="index.php?option=com_content&view=article&id=133&Itemid=63">AAAAA[/url]</p></td>
<td width="12" height="35" align="center" valign="middle" bgcolor="#ffffff">
<div>S</div></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff">d</td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td width="20" height="35" valign="middle" bgcolor="#ffffff"></td>
<td height="35" align="center" valign="middle" bgcolor="#009933"> </td>
</tr>
<tr>
<td width="120" height="35" valign="middle" bgcolor="#ffffff"><a href="index.php?option=com_content&view=article&id=145&Itemid=63">BBBBB[/url]</td>
<td width="12" align="center" valign="middle" bgcolor="#ffffff">
<div>S</div></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td valign="middle" bgcolor="#ffffff"></td>
<td align="center" valign="middle" bgcolor="#009933"> </td>
</tr>
<tr>
<td width="120" height="35" valign="middle" bgcolor="#ffffff">
<p><a href="index.php?option=com_content&view=article&id=148&Itemid=63">CCCCC[/url]</p></td>
<td width="12" align="center" valign="middle" bgcolor="#ffffff">
<div>P</div></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" align="center" valign="middle" bgcolor="#009933"> </td>
<td width="20" align="center" valign="middle" bgcolor="#009933"> </td>
<td width="20" align="center" valign="middle" bgcolor="#009933"> </td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
<td width="20" valign="middle" bgcolor="#ffffff"></td>
</tr>
</tbody>
</table>