Website works great in FF but not in Chrome and IE

[QRS5]

Hey guys I got a problem on my phpBB3 forum, mostly FF and Chrome works great together and looks pretty much the same when you do the CSS, but not in my case, I have a chat box where in FF the text is floated to the left perfectly but not in IE and Chrome, linking pictures:




I can't see what really is the problem.
These are the CSS properties.

/**
*
* @package mChat ProSilver Style
* @version 1.3.5 2010-12-02
* @copyright (c) RMcGirr83 ( http://www.rmcgirr83.org/ )
* @copyright (c) By Shapoval Andrey Vladimirovich (AllCity) ~ http://allcity.net.ru/
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
**/

/* mChat
------------ */
div.mChatBG1 {
	background-color: #FBFBFB;
	padding: 5px 5px 5px 5px;
	border-bottom: 1px dotted #DDDDDD;
	overflow: hidden;
}

div.mChatBG2 {
	background-color: #FFFFFF;
	padding: 5px 5px 5px 5px;
	border-bottom: 1px dotted #DDDDDD;
	overflow: hidden;
}

div.mChatRowLimit {
	overflow: auto;
	width: 100%;
}

div.mChatRowLimitCustom {
	overflow: auto;
	width: 100%;
}

div.mChatPanel {
	text-align: center;
	padding: 3px;
	clear: both;
}

input.mChatText {
	cursor: text;
	width: 50%;
	background-color: #FFFFFF;
	border: 1px solid #B4BAC0;
	color: #333333;
	padding: 5px 5px 3px 5px;
	margin: 3px 0px 3px 5px;
}

input.mChatText:hover {
	border-color: #11A3EA;
}

div.mChatHover:hover {
	background-color: #F6F4D0;
}

div.mChatBodyFix {
	width: 100% !important;
	background-color: #E9F0F5 !important;
}

div.mChatStatic {
	padding-left: 5px;
	font-family: "Lucida Grande", Verdana, Helvetica, Arial, sans-serif;
	text-align: left;
	font-size: 1.1em;
}

div.mChatStats {
	padding-left: 5px;
	margin-top: 2px;
	font-family: "Lucida Grande", Verdana, Helvetica, Arial, sans-serif;
	text-align: left;
	min-height: 1.3em;
	font-size: 1.1em;
	height: auto !important;
}

div.mChatRefresh {
	padding-left: 5px;
	font-family: "Lucida Grande", Verdana, Helvetica, Arial, sans-serif;
	text-align: left;
	font-size: 1.1em;
	margin-top: 1.5em;
	clear: both;
}

input.mChatColor {
	width: 100%;
	text-align: center;
	background-color: #DEE3E7;
	border-style: none;	
}

div.mChatMessage {
	padding: 3px;
	font-size: 1.1em;
	width: 98%;
	text-align:left;
	margin:5px;

}

a.mChatScriptLink {
	text-decoration:none;
}

img.mChatImage{
	vertical-align: middle;
}

img.mChatImageLoad {
	vertical-align: middle;
	cursor: wait;
	display: none;
}

img.mChatImageOk {
	vertical-align: middle;
	cursor: help;
}

img.mChatImageHideImg {
	vertical-align: middle; 
	cursor: help; 
	display: none;
}

div.mChatSound {
	position: absolute;
	left: -1000px;
	top: -1000px;
}

.mchat_alert {
	color: #7E2217;
	padding: 10px;
}

#mChatUserList {
	display: none;
	float: left;
}

.mChatAvatars {
	float: left;
	padding-right: 5px;
}

div.avatarMessage {
	margin-left: 50px;
	width: 90%;
	margin-right: 5px;
}

And the HTML:

<div class="postbody mChatBodyFix">
<script type="text/javascript">
<script type="text/javascript" src="./styles/modestus/template/editor.js"/>
<div id="mChatmain" class="mChatRowLimit" style="height: 250px; ">
<div id="mChatData">
<div id="mess1" class="mChatBG1 mChatHover">
<div id="mess2" class="mChatBG2 mChatHover">
<span style="float: left; ">
<span style="float: right; ">
<a href="./mchat.php?mode=whois&ip=81.237.111.86" onclick="popup(this.href, 750, 500); return false;">
<a href="javascript://" onclick="mChat.edit('2');">
<input type="hidden" id="edit2" value="UPDATE - check the Event section!"/>
<a href="javascript://" onclick="mChat.del('2');">