Simplify tech support got back to me with the following May 13, 2014 although I don't know if it resolved the problem since I abandoned my prestashop install when I couldn't accept simplify payments.
This info could now be outdated.
Please update if it resolved the problem I may try another prestashop install!
MAY 13, 2014 | 07:48AM CDT Tom O. replied:
Hi,
Apologies for taking so long to get back to you. Unfortunately, the plugin had the incorrect version of PHP specified on the configuration page. The plugin in fact requires PHP 5.3+ and so using a lower version of PHP or the 5.2 as specified will cause the error you encountered. If you upgrade your version of PHP to 5.3 or above, the issue should be resolved.
We have updated the plugin accordingly with the correct version of PHP to use which you can find at: https://github.com/simplifycom/simplify-prestashop-module/releases/download/v1.0.1/simplifycommerce.zip
We appreciate your mail and informing us of the issue. If you have any other feedback or improvements you’d like to see, then do let us know and we’d be happy to help you out.
Thanks, Tom