There's a WAY easier way. Highlight the fields in calc and select them - do not highlight header fields, just highlight the data. Copy to the clipboard (edit - copy).
Make a backup of your Base file in case something goes wrong. Now open your Base file, but, this is important, do not open the table. Select Tables from the Database area on the left. Now, just click, once, on the table to which you want to import your data, only click one time to select it but don't open it. Right click. Select paste, and a wizard pops up that asks you how to import the data. Follow those instructions and the data will be imported into your table as specified. In the next screen, the wizard will show you the first row of what is being imported and will show you the fields from the table that each imported column will map to, and there you can make any changes so that the columns go into the proper database fields.
So for example, if the database fields are FirstName & Lastname, and the first row of your data is Smith, Tom, the wizard will tell you it's going to map the column containing Smith to FirstName and the column containing Tom to LastName, which is exactly backwards, so swap the field names and press OK. Your data will be imported. Double click on the table and there it will be.