price list import problem

price list import problem

I am trying to import a price list. But not successful. The error is: 
  • CSV-Kopfzeilen dürfen nur Artikelname, Preislistentarif und Artikelpreis enthalten. Bitte überprüfen Sie die Kopfzeilen.
It is in German, but it means, CSV header is only allowed to be  Artikelname, Preislistentarif andArtikelpreis.

I don't know where is the problem. I have checked my file. It does contain only these three column headers.
I have even deleted SKU column, which is included by the exported templates..