Errors when activating plugins

I have several WP sites on a godaddy Linux Ultimate hosting account that I have been experimenting and learning from. All was okay until I had to renew my SSL and change my primary domain name. Now all my WP sites (except 1) are either giving errors or just stopped working. I have even tried completely deleting everything (including the database) and starting new but it goes fine until I try to activate a plugin (e-commerce or phpurchase) then I get a fatal error, example below. I should also note that along with losing my WordPress sites I have also lost 2 phpBB3 forums!
To see this error go here where at this point all I have done is to install WP and then tried to install the WP e-commerce plugin!
To see the one working site that was not lost during this go here. This site had one error from an unsued plugin so I removed it and all appears fine and it still has a dozen plugins (including WP e-commerce) installed!

Please help, what am I missing? I am still fairly new to WP and PHP in general but not to html ect.

Thank you for taking the time to read this and helping!
Ken