Hi,
Can you reproduce the issue in our demo website ?
I made a test in the demo website (the product edition in the backend ; which use the same upload library) and the upload was fine (the demo website does not allow the thumbnail generation but the file was uploaded).
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.