tabulka neni na stredu

ahoj mam problem s tabulkou... v FF je na stredu v IE neni :(

na strance http://rkliberec.dumapes.cz
ta níž (nejnovejsi poptavka)

neni na stredu proste nelicuje nechapu proc... :(

html:

<div align="center">
<table class="table_obsah" style="width: 540px">
<tr>
<td class="table_nadpis">Zajímavá nabídka</td>
</tr>
<tr>
<td>
<table style="width: 100%">
<tr>
<td class="table_nadpis_sub" style="width: 75px">
Foto</td>
<td class="table_nadpis_sub" style="width: 260px">
Typ,Lokalita, Popis</td>
<td class="table_nadpis_sub" style="width: 100px">
Cena</td>
<td class="table_nadpis_sub" style="width: 18%"> <strong>&gt;&gt;Zobrazit&lt;&lt;</strong></td>
</tr>
<tr class="table_obsah_bunka1" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka1'">
<td style="width: 75px" valign="top">
<img src="image/25758_1.jpg" width="75" height="56"></td>
<td style="width: 260px">&nbsp;Byt 3+1, Liberec -
Staré Město...</td>
<td style="width: 100px">2850000,- Kč</td>
<td style="text-align:center; width: 18%;"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr class="table_obsah_bunka2" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka2'">
<td style="width: 75px" valign="top">
<img src="image/byt-x.jpg" width="75" height="56"></td>
<td style="width: 260px">Garsonka, Liberec - Vesec,
po rekonstrukci...</td>
<td style="width: 100px">1200000,-Kč</td>
<td style="text-align:center; width: 18%;"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr class="table_obsah_bunka1" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka1'">
<td style="width: 75px" valign="top">
<img src="image/soukromy-byt-6.jpg" width="75" height="56"></td>
<td style="width: 260px">Dům 5+1, dvě podlaží,
zahrada 300m2, výborná dostupnost MHD...</td>
<td style="width: 100px">3500000,-Kč</td>
<td style="text-align:center; width: 18%;"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr>
<td colspan="4" style="text-align:center"><strong>
<a href="/nabidka-nemovitosti">&gt;&gt;Zobrazit všechny
nabídky&lt;&lt;</a></strong> :: <strong>
<a href="/form/prodat-nemovitost/prodat-nemovitost.htm">&gt;&gt;Vložit
nabídku&lt;&lt;</a></strong></td>
</tr>
</table>
</td>
</tr>
</table>
</div>

<br>
<div align="center">
<table class="table_obsah" style="width: 540px">
<tr>
<td class="table_nadpis">Nejnovější poptávka</td>
</tr>
<tr>
<td>
<table style="width: 100%">
<tr>
<td class="table_nadpis_sub" style="width: 64px">
Datum</td>
<td class="table_nadpis_sub" style="width: 345px">Popis</td>
<td class="table_nadpis_sub"> <strong>&gt;&gt;Zobrazit&lt;&lt;</strong></td>
</tr>
<tr class="table_obsah_bunka1" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka1'">
<td style="width: 75px" valign="top">14.02.2008</td>
<td style="width: 345px">Koupím byt 3+1 v Liberci na Králově háji s
balkónem... </td>
<td style="text-align:center"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr class="table_obsah_bunka2" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka2'">
<td style="width: 75px" valign="top">10.02.2008</td>
<td style="width: 345px">Garsoniéru v centru Liberce. Důležitá dobrá...</td>
<td style="text-align:center"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr class="table_obsah_bunka1" onmouseover="this.className='table_obsah_bunka_hover'" onmouseout="this.className='table_obsah_bunka1'">
<td style="width: 75px" valign="top">07.02.2008</td>
<td style="width: 345px">Koupím chalupu v Jizerských horách.
Maximální cena... </td>
<td style="text-align:center"><a href="/index.htm">
&gt;&gt;Zobrazit&lt;&lt;</a></td>
</tr>
<tr>
<td colspan="3" style="text-align:center"><strong>
<a href="/poptavka-nemovitosti">&gt;&gt;Zobrazit všechny
poptávky&lt;&lt;</a></strong> :: <strong>
<a href="/form/koupit-nemovitost/koupit-nemovitost.htm">
&gt;&gt;Vložit poptávku&lt;&lt;</a></strong></td>
</tr>
</table>
</td>
</tr>
</table>
</div>


css:
/* tabulky */
table {border:none;font-size:12px;margin:auto;}
.table_nadpis {background-color:#3c67c1;border-bottom:5px double #3c67c1;font-weight:bold;color:white;text-align:center}
.table_nadpis_sub {background-color:#d1dffb;border-bottom:5px double #d1dffb;font-weight:bold;text-align:center}
.table_sloupec {border:2px solid #bfbfbf;width:180px;background-color:#eef2ff}
.table_obsah {width:540px;align:center;border:2px solid #bfbfbf}
.table_obsah_bunka1 {background-color:#f7f7f7}
.table_obsah_bunka2 {background-color:#e5e5e5}
.table_obsah_bunka_hover {background-color:#eef2ff}

no to funguje, tabulky sou ok, ale uplne mi to rozhazi jiny veci :(

to nepomaha :( nemuze to byt tim ze uz mam v css tohle: * {-moz-box-sizing:border-box;box-sizing:border-box }