Error adding new records in an user table

Hi

I'm trying to add a new record in an user table, and after calling the add method I get the next error message:

"Generating this document requieres numbering to be determined for the document".

I've defined my user table as Master Data, and the source code is as follows:

dim m_UserTable as SAPbobsCOM.UserTable

m_UserTable = SboCompany.UserTables.Item(UserTable)

m_usertable.Code = NewValue

m_usertable.UserFields.Fields.Item("U_FIELD1").Value = NewValue

if m_userTable.add() <> 0 then

SboCompany.GetLastError(lngError, strerror)

SboApplication.MessageBox(strerror)

end if

Thanks and Best Regards

Dani