Hello,
This problem relates to some 3-rd party plugin that you use, so try to disable 3-rd party plugins (means the plugins that are not included in the theme package are not in the list of required plugins).
We are able to help you with issues related to our theme options or bugs only. Feel free to contact us if you have questions about our theme settings.
Also, check these requirements http://xstore.helpscoutdocs.com/article/60-xstore-theme-requirements and update your server settings according to these requirements.
Regards