When I try to do the transfer, it keeps saying that I do not have headers on the excel sheet, but I do have headers. I've even tried to transfer just the email addresses and names, but the same problem occurs. Can anyone help please!

Have you tried saving your spread sheet as a .csv file and then importing that into Outlook. Click on Import_Other Address Book and select Text File (comma separated values) and then browse to your file and it should work. Hope that helps

Try to save your excel file as CSV before you import it in outlook
(File - Save As - in Save as type select CSV (Comma delimited))