Hi Guys! I had the same error of selectshop.at #8 during a migration between domain to domain with differente php version, I have installed prestashop 1.6.0.14 with 5.3.29 php version in a original domain and moved in a new domain with 5.6.9 php version and not has working more I have solved going to my php hosting settings of the second domain and choosing a 5.3.29 or 5.4.41 or 5.5.25 php version and the site returned to work immediatly, instead setting the 5.6.9 php version not working more.
Have a nice day!