Another possible cause of this "invalid field count in CSV input on line 1" error is that the file you are importing is not actually CSV format. The filename might end in ".CSV" but could actually be a different format, usually Excel binary / XLS format.
The fix is to "Save As" and change format to CSV, in your Spreadsheet application (Excel, OpenOffice Calc, Numbers, etc). Upload the new file you just saved in actual CSV format.