Hi,
I think the error message is just the right seeing the context.
You have made a translation override and the problem is that, you put a limitation of the item in the cart (Maximum quantity per order). So when you try to add the product a second time, HikaShop refuse and give you a error message (which has been translated and which does not feet to this exact context).
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.