Try each these steps in order until the issue or error is resolved:
  1. On the Import parameter's Fields tab, ensure there are not yellowed lines at the bottom of the Fields to Import.  
         a. If there are, highlight and click Remove
    1. b. Click clear field on bottom right and then update fields
  2. Update the Fields on the Import parameter (NOTE: If the header fields are not the defined RE field headers, clicking 'Update Fields' will remove any manual mapping that has occurred).
    1. In Administration, click Import and open the Import parameter.
    2. Select the Fields tab and click the Clear Fields button
    3. Click the Update Fields button
  3. Open the import file.  Verify that the import file does not contain any blank fields or columns.  If it does:
    1. Open the data file in Notepad 
    2. Remove extra fields (blank columns in Excel) deleting extra commas.
      For example, look at the following data:
      Joe, Smith, 123 ABC St., Charleston, SC, 29407,,,,
      Each comma acts as a delimiter for a field (column in Excel).  Therefore, Joe is a field, Smith is a field, 123 ABC St. is a field, Charleston is a field, SC is a field, and 29407 is a field.  However, there are also four blank fields at the end of the data file.

      Note: The extra fields (or columns) may also be deleted directly from Excel. Open the data file in Notepad to determine how many blank columns there are. Then, delete those columns in Excel. In the example above, columns G-J are deleted in Excel.

      4. If using header records, ensure there are no columns without a header record
      5. If not using header records, ensure that all of the fields to import are matched up with a Raiser's Edge field on the Fields Tab
      6. Recreate the import rather than using the saved import parameters

 If the error is still occurring:
  1. Copy and paste all the fields and headers into a new spreadsheet 
  2. Save as a CSV file
  3. Import records using the new file