Problem authenticating since upgrade

Hi,

I have been doing some development in a separate test environment (ie not multisite) in a subdomain of the main website. The facebook plugin has been working fine in test and have made small changes to formatting etc no problem. The live installation of the plugin is still activated and working fine also.

Before rolling the new environment into live I wanted to upgrade everything, so upgraded to wordpress 4.0 and the latest version of ultimate facebook. Plugin was still working fine after this.

Unfortunately, I didn't set auto upgrade off for wordpress and it upgraded to 4.01 automatically. It was only then that I noticed that ultimate facebook wasn't working anymore. On looking at the plugins page I saw that there was also a new version of the plugin available so I installed that - version 2.7.9. Still not working with the following error in error log:
November 26, 2014 3:05 am Unknown get_album_photos exception Invalid OAuth access token.

I am doing a get of an album using a short code on a single page and am making use of no other functionality (tried using the widget instead - still no action). Like I said, this is still working in live with the same album id.

I have tried resetting id, secret and auth code in plugin settings and reactivating plugin. I have also created a new separate app in facebook just for the test environment and hooked into that instead. Still getting the same error.

I can't commit to rolling the new website into live until this is resolved in the test environment. As it was working and then stopped after the upgrade to wordpress 4.01 seems likely it will stop working also in the live website if I were to migrate test across.

Any assistance will be much appreciated.

Greg