Hi,
Regarding the error message ; I'm afraid that you have been hacked.
As you can see in the incriminated files, HikaShop is not related to your issue, but the recent security issue in Joomla could be related.
Please re-install Joomla in your website in order to use the official files and be sure that nothing has been modified.
For more details ; please use the Joomla support forum.
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.