When attempting to create a user using the API the following error occurs.

Passing in a hash with user information:
*Debug(8)* do_request: Sending: {"auth":"dc935f65ee558417ba82427840b0189c","id":8,"method":"user.add","params":

{"name":"test","theme":"default.css","autologout":900,"type":3,"autologin":0,"url":"","rows_per_page":50,"refresh":60,"lang":"en_GB","password":"test","alias":"testapiuser"}

,"jsonrpc":"2.0"}
*Debug(8)* do_request: Response Code: 200
*Debug(8)* do_request: Response Body: {"jsonrpc":"2.0","error":

{"code":-32500,"message":"Application error.","data":"Unknown ZABBIX internal error"}

,"id":8}

Passing an array with one hash:
*Debug(8)* do_request: Sending: {"auth":"3fa1184402969060c95657773766c056","id":8,"method":"user.add","params":[

{"name":"test","theme":"default.css","autologout":900,"type":3,"autologin":0,"url":"","rows_per_page":50,"refresh":60,"lang":"en_GB","password":"test","alias":"testapiuser"}

],"jsonrpc":"2.0"}
*Debug(8)* do_request: Response Code: 200
*Debug(8)* do_request: Response Body: {"jsonrpc":"2.0","error":

{"code":-32500,"message":"Application error.","data":"Unknown ZABBIX internal error"}

,"id":8}

As a side note it's not very clear what the minimum number of arguments are for creating a user.