Hi,
I think that you have a widget with an "incorrect" configuration.
Even if you can't display the dashboard you should be able to display the widget listing and unpublish (or delete) the widget with the issue.
/administrator/index.php?option=com_hikashop&ctrl=report
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.