Problemas con FireFox

[edugonch]

Tengo una consulta que hacer sobre la renderización de una página web en IE y FF, en ambos se ve diferente y no se como puedo hacer para que solucionar el problema, por ejemplo, este es un fragmento de código de la página, las esquinas de la tabla son redondeadas con imágenes, este fragmento de código SE VE BIEN en ambos exploradores:


<!-- Place the Shopcart short cut here -->

<tr>

<td colSpan="3"><div style="LEFT: 29px; POSITION: relative">

<IMG style="POSITION: relative;TOP: 14px;LEFT: 0px;Z-INDEX: 2" height="11" src="images/Inside_TopLeft.gif" width="11">



<IMG style="POSITION: relative;TOP: 14px;LEFT: 135px;Z-INDEX: 2" height="11" src="images/Inside_TopRight.gif" width="11">

<table class="main_B2_L2_R2_T2" height="120" cellSpacing="0" cellPadding="0" width="160">

<tr height="20">

<td width="100%">

<table width="100%" style="TABLE-LAYOUT: fixed">

<tr>

<td width="25%" valign="top">&nbsp;&nbsp;<span id="ShopCart1_Label1" style="font-weight:bold;">Cart : </span></td>

<td width="75%" style="WIDTH: 100px; WORD-WRAP: break-word"><span id="ShopCart1_lblCart"></span>&nbsp;</td>

</tr>



</table>

</td>

</tr>

<tr height="20">

<td>

<table>

<tr>

<td width="60%">&nbsp;&nbsp;<span id="ShopCart1_Label3" style="font-weight:bold;">Items in Cart : </span></td>



<td align="center"><span id="ShopCart1_lblItems"></span>&nbsp;</td>

</tr>

</table>

</td>

</tr>

<tr height="20">

<td><table>

<tr>

<td width="45%">&nbsp;&nbsp;<span id="ShopCart1_Label5" style="font-weight:bold;">Sub-Total : </span></td>



<td align="right"><span id="ShopCart1_lblSubt"></span>&nbsp;</td>

</tr>

</table>

</td>

</tr>

<tr height="30">

<td align="middle">

<a id="ShopCart1_goToButton" disabled="disabled" class="GoToCartButton" href="http://argonaut/SnapTrackerWeb/default.aspx?IMN_Id=121" style="height:20px;">Go to Cart</a>



<a id="ShopCart1_lbtnDummy" href="javascript:__doPostBack('ShopCart1$lbtnDummy ','')"></a>

</td>

</tr>



Ahora, este otro fragmento de Código tiene problemas en firefox, en IE se ve perfecto, me gustaría saber que puede ser el problema y como solucionarlo:



<div id="_x_1_HeaderControl1_pnlCustomer">



<TD >



<IMG style="Z-INDEX: 1; LEFT: 413px; POSITION: relative; TOP: -44px" height="11" src="images/Top_Left.gif" width="11">

</TD>

<TD >

<IMG style="Z-INDEX: 1; RIGHT: -532px; POSITION: relative; TOP: -44px" height="11" src="images/Top_Right.gif" width="11">

</TD>

<!--<TD align="right"><IMG class="custSelectLeftNET" src="images/Customer_left.gif">

</TD>-->

<TD class="custSelect">



<DIV>

<span id="_x_1_HeaderControl1_AvailableCustomerListContr ol1_Label1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;&nbsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;&nbsp;&nbsp;&nbsp;</span>



<span id="_x_1_HeaderControl1_AvailableCustomerListContr ol1_lblText">Select a Customer</span>

<select name="_x_1:HeaderControl1:AvailableCustomerListCon trol1:CustomerDropDownList" id="_x_1_HeaderControl1_AvailableCustomerListContr ol1_CustomerDropDownList" class="medium" onchange="__doPostBack('_x_1$HeaderControl1$Availa bleCustomerListControl1$CustomerDropDownList','')" language="javascript">

<option selected="selected" value="ABACHELOR">A - BACHELOR - BACHELOR</option>

<option value="ACRUNCH">A - CRUNCH - CRUNCH</option>

<option value="ADUMMY">A - DUMMY - DUMMY CUSTOMER</option>

<option value="AM-PONY">A - M-PONY - M-PONY</option>



<option value="AMARIOS">A - MARIOS - MARIOS</option>

<option value="AMARIOS2">A - MARIOS2 - MARIOS</option>

<option value="AMARIOS3">A - MARIOS3 - MARIOS3</option>

<option value="APRESOLD">A - PRESOLD - Pre-sold goods</option>

<option value="Atest01">A - test01 - test01</option>

<option value="ATESTPRE">A - TESTPRE - TESTPRE</option>



<option value="BBACHELOR">B - BACHELOR - TESTING</option>

<option value="BTESTCOB">B - TESTCOB - TEST CUSTOMER FOR COMPANY B</option>

<option value="CBOMBA">C - BOMBA</option>

<option value="CCRUNCH">C - CRUNCH - CCCCCCCCCCCCCCC - CRUNCH</option>

<option value="DDS-001">D - DS-001 - some d</option>

<option value="Dsumsa">D - sumsa - sumsarra sara</option>



<option value="ZFB">Z - FB - fly boy zippy</option>



</select>





</DIV>

</TD>

<!--<TD><IMG class="custSelectRightNET" src="images/Customer_right.gif"></TD>-->

<TD>

<IMG style="Z-INDEX: 1; LEFT: 37px; POSITION: relative; TOP: -5px" height="11" src="images/Bottom_Left.gif" width="11">

</TD>



<TD>

<IMG style="Z-INDEX: 1; RIGHT: -156px; POSITION: relative; TOP: -5px" height="11" src="images/Bottom_Right.gif" width="11">

</TD>



</div>