After login checkout and bank transfer error

-- HikaShop version -- : 2.3.4
-- Joomla version -- : 3.3.0
-- PHP version -- : 5.5.19
-- Browser(s) name and version -- : Firefox 32.0
-- Error-message(debug-mod must be tuned on) -- : Results consisted of more than one row in sql

The hikashop checkout give error after the blank transfer and place order gives error.
Please see the attached screenshot for the reference now.

Hi,

This don't seem to be an HikaShop issue, but an issue related on your modifications or an external component.
We don't have table "master_user" in HikaShop.