In need of help, plugin works but breaks admin

Hi this is a bit of an odd problem. I finally got my plugin for showing the latest photos in zen photo working. But now as long as its active when ever I submit a post, the post is submitted but im left with a blank page instead of the post confermation page.

Below is the code for my plugin, could anyone give any light on what is wrong?

code
<?php

/*
Plugin Name: ZenGo
Plugin URI: https://www.photogabble.co.uk
Description: Displays the recent additions to the zenphoto gallery
Version: 0.5
Author: Simon Dann
Author URI: https://www.photogabble.co.uk
*/

function zenlatest ($max){
global $wpdb;
if ($max == “”) { $max = 1; }

$zenimages = $wpdb->get_results(“SELECT zen_images.filename AS filename, zen_images.desc AS file_desc, zen_album.folder AS folder, zen_images.title AS title FROM zen_images AS zen_images INNER JOIN zen_albums AS zen_album ON zen_album.id = zen_images.albumid WHERE zen_images.show =1 ORDER BY zen_images.id DESC LIMIT 0, ". $max ."");

foreach ($zenimages as $zenimage ) {<br />
echo '<a>folder .'/'. $zenimage->filename . '"><img src="/zenphoto/'. $zenimage->folder .'/image/thumb/'. $zenimage->filename .'"></a>';<br />
}

}
code`