What is wrong with my plugin?

[SnickersTK]

Hook Location = Newpost_preview

PHP Code:

$bbcode_pattern = '/\\[mod=(\\d+)\\]/';
$bbcode_replacement = '<table width="90%" cellspacing="1" cellpadding="3" border="0" align="center">
<tr>
<td><span class="smallfont"><strong>Moderator Warning:</strong></span></td>
</tr>
<tr>
<td class="modscode"><img align="left" src="http://www.[Censored].com/UH/BBcodes/images/mod.gif">$1</td><tr></table> ';
if(preg_match($bbcode_pattern, $previewmessage))
{
    $previewmessage = preg_replace($bbcode_pattern, $bbcode_replacement ,$previewmessage);
} 


If I write: [mod=test] and press preview, it just writes the exact same

oh this is the css I added:

.modscode{font-family: Courier, Courier New, Verdana, Arial;
	color: #465584;
	background-color: #FAFCFE;
	border: 1px dotted #000;
	padding: 2px;
	width:98%;
	margin: 0px auto 0px auto;
	/*overflow: auto;
	height: 200px;*/}

it doesn't do the code... unless I write numbers (Ex: 1,2,3,4)

Ok, how to make [high]d+[/high] into [high][a-z,A-Z,0-9][/high] and still having the code working ( $bbcode_pattern = '/\\[mod=(\\d+)\\]/'; )

and should I do anything about [high]$1[/high] ?

and if I didn't make it clear... I need to be able to write alot. Ex: [mod=look at me I am typing]

Thanks!