Fatal Error in fgauto.php PopUpGallery plugin

I have installed the excellent PopUpGallery plugin from https://wp-plugins.net/www.yellowswordfish.com and got it installed OK. I have configured it and it seems to do that fine.

The problem comes when trying to add a gallery.

I fill in the fields regarding where to find the photo’s and the sizes and dimensions I require, then when I click the button to create the gallery I get the following error

Fatal error: Only variables can be passed by reference in /fgauto.php

this is at line 190 in fgauto.php

I have checked with the author and he suggested it may have been too many full stops in the filename, I have checked and there is only one in each filename before the file extension as expected.

I have also done the usual google search and found that this may well be due to a change in PHP recently which has rendered a lot of code in-operative.

I am running WordPress under Ubuntu 5.10 Breezy Badger, installed using apt-get.

I have php5.05 again installed using apt-get

I have installed all the available modules for php5 and restarted my apache web server (Apache 2) and still get the error.

I have changed permissions on the folder containing the images and also changed permissions on the images themselves, still no luck.

I would be very grateful if someone with significantly more PHP experience than me could have a look at the fgauto.php file and let me know a hack/fix for it that will get the code to comply with the new changes in php5.05

Thanks

Adam