Hello,
Your error is not a Fatal error but a warning coming from a view override in your template.
That is unfortunately not the fatal error and you should activate temporally the Joomla debug mode (in the Joomla global configuration) in order to see directly the error message in your website.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.