I have downloaded a demo version of the software and use the general way to create the database using the default values. I was able to add and create the table the way I wanted. I am using Windows 8.1 Pro X64 and everything worked well. The program was launched with Administrator access to enable write to disk for system partition. You can do the same, but if you still encounter errors, choose another database format when opening the file even if it's in DBF format.