Hi,
When you create a custom field, you have to provide a "field namekey".
That namekey is also the column name that you'll find in your database.
You have to be sure that you have the corresponding column in your database.
The first step would be to perform a "check database" (button in the toolbar while you're in the HikaShop configuration).
Then, if the problem persist, you'll have to check your custom field configuration and look at your HikaShop tables.
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.