The fix for this problem can be found here:
Another tip for Excel users. If you want to convert XLS to CSV, one very simple way to do it is to log into Google Docs and create a new spreadsheet. Do a File > Import… and select your Excel document. (supports .xls, .xlsx, .ods, .csv, .txt)
After importing you will see an “Open now” link. Click it.
Now, from your newly imported spreadsheet do a File > Download as > .csv
This file, with quotation marks around all values (and a comma at the end of each line except the header line) will import successfully. Believe me, I struggled with this for a while until finding this answer!