Error on Modules page

[ChrisMillard]

I have inherited a 1.4.0.17 Prestashop which I would like to upgrade.

 

I have duplicated the site onto a subdomain and am attempting to install 1 click upgrade.

 

However the modules page show the following error.

 

Fatal error: Class 'Shop' not found in /home/xxxxxx/public_html/modules/avalaratax/backward_compatibility/Context.php on line 254

 

The problem occurs on both the live and my test subdomain. I tried using the latest version of the avalaratax module, by replacing the folder with the latest download but same error (maybe different line)

 

If I rename the avalaratax folder in and attempt to disable it I get this error.

 

Fatal error: Class 'eBayCountrySpec' not found in /home/xxxxxx/public_html/classes/Module.php(408) : eval()'d code on line 117

 

Any help would be appreciated.