Looks like something wrong in the addition fields data definition.
Feel free to email me the results of these two MySQL queries.
SELECT * FROM sys_man_additional_fields;
and
SELECT * FROM sys_man_additional_fields_data;
Email the results to support@opmantek and I'll take a look.
Update: I tried adding a single device using the spreadsheet. The update was successful but I still received the above error message. Thinking this would work for multiple devices, I tried adding 10+ devices. The received the above error message but the addition of devices didn't occur in open-audit.