The import record update utility requires a file saved in a csv file format. It is likely that the file was saved as a text file instead.

To convert a txt file to a csv
  1. Open FIMS and open the file to be imported.
  2. Click file save as
  3. Choose comma-delimited (CSV).  Be careful not to choose one of the variations.
  4. Try your import again.

If this doesn't resolve your issue there is likely a different problem with the content of the columns.