Hello,
A PHP warning is not a bug, it is just a warning.
And such kind of PHP message should be not visible in a production website ; they can be logged in a file but not displayed to the final user.
Afterwards, I'm sorry but I don't understand the link between the subject of your topic and the reste of your message.
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.