This is the simplest method to unzip a file. Pass the function your filename and it will unzip it to the current directory of the script with permissions done properly on unix type operating systems. Far simpler to understand and read.

<?php
function unzip($file){
    $zip = zip_open($file);
    if(is_resource($zip)){
        $tree = "";
        while(($zip_entry = zip_read($zip)) !== false){
            echo "Unpacking ".zip_entry_name($zip_entry)."\n";
            if(strpos(zip_entry_name($zip_entry), DIRECTORY_SEPARATOR) !== false){
                $last = strrpos(zip_entry_name($zip_entry), DIRECTORY_SEPARATOR);
                $dir = substr(zip_entry_name($zip_entry), 0, $last);
                $file = substr(zip_entry_name($zip_entry), strrpos(zip_entry_name($zip_entry), DIRECTORY_SEPARATOR)+1);
                if(!is_dir($dir)){
                    @mkdir($dir, 0755, true) or die("Unable to create $dir\n");
                }
                if(strlen(trim($file)) > 0){
                    $return = @file_put_contents($dir."/".$file, zip_entry_read($zip_entry, zip_entry_filesize($zip_entry)));
                    if($return === false){
                        die("Unable to write file $dir/$file\n");
                    }
                }
            }else{
                file_put_contents($file, zip_entry_read($zip_entry, zip_entry_filesize($zip_entry)));
            }
        }
    }else{
        echo "Unable to open zip file\n";
    }
}
?>