background image in table <td> different in IE and Firefox

[belper]

Hello,

I have this php code :

//echo $i."<br>end-".$end."-start-".$start;
       	echo "<table bgcolor=#666666 bordercolor=#C0C0C0 border=0 width=700 cellspacing=0 cellpadding=10><tr><td background=\"images/topbar.gif\" height=\"45\"></td></tr><tr><td>";
        	echo "<b>$listDatetxt: </b>";
        $lines[$i]->showDate();
	echo "<br><b>$listnametxt: </b>";
        $lines[$i]->showFrom();
        echo "</a><br><br><b>$listMessagetxt: </b>";
        $lines[$i]->showMessage();
	echo "</td></tr>
	<tr><td background=\"images/footbar.gif\" height=\"30\"></td></tr></table><br>";
}

echo "<center>";

This is the problem :

In Firefox the table is shown correctly, except that text is not centered
In IE text is centered but the background images (topbar and footbar) seam to be ‘repeated’ in the in the imagebar.
Sizes of my images :
topbar.gif 700x45
footbar.gif 700x30
So obviously I am doing something wrong (newbee !)
Someone can help me ?

Thanks