PHP Fatal Error

Hi,

i got this message..

PHP Fatal error: Only variables can be passed by reference in /wp-content/plugins/multiple-post-thumbnails/multi-post-thumbnails.php on line 158

i got more instances of the plugin in my funkctions.php
if (class_exists(‘MultiPostThumbnails’)) {

new MultiPostThumbnails(array(
‘label’ => ‘Flyer Image’,
‘id’ => ‘flyer-image’,
‘post_type’ => ‘post’
) );

new MultiPostThumbnails(array(
‘label’ => ‘Gallery Image’,
‘id’ => ‘gallery-image’,
‘post_type’ => ‘post’
) );

new MultiPostThumbnails(array(
‘label’ => ‘Lageplan Image’,
‘id’ => ‘map-image’,
‘post_type’ => ‘post’
) );

new MultiPostThumbnails(array(
‘label’ => ‘The Club Image’,
‘id’ => ‘club-image’,
‘post_type’ => ‘post’
) );

}

Site = http://www.doclx-clubs.at

any hints?

Thx
Chris

https://wordpress.org/plugins/multiple-post-thumbnails/