This knowledgebase explains how to solve the "Skip import row, required field "sku" not defined" or "Skip import row, required field "store" not defined"error when importing products via a .CSV file into Magento using Magento Import / Export Profiles.
In most cases your .CSV file needs to be saved in UTF-8 format:
1. First, ensure all your fields are properly filled in Excel or Open Office Calc.
2. Create and edit a copy of your original .CSV file (in case it goes pear shaped).
3. Save the file as Comma Separated Values (.CSV) if you haven't already done so.
4. Open the file with a text editor such as NOTEPAD or TEXTEDIT (if using a Mac).
5. Go to File > Save As Your filename should end with .csv. Example: import.csv
6. Under Save as type select All files (*.*)
7. Under Encoding (Plain Text Encoding in TEXTEDIT) select UTF-8
8. Save the file ready for reimporting into Magento