1. In Administration, Import records, open the import parameters.
2. Select the Fields tab.
3. Select the blank row and click Remove.
4. Run the import again.

If there are no blank rows:
1. In Administration, Import records, open the import parameters.
2. Select the Fields tab.
3. Click Clear Fields.
4. Click Update Fields.
5. Run the import again.

If the exception continues to appear:
Make sure that the import file is in CSV format.  If the file is in Excel format, the program may not be able to read the fields properly, resulting in this exception.