I have been trying to upload my collection and getting this error

Errors have been found while checking the CSV file. The errors are shown below. Please fix them and try to check the file again.
Reg Qty Foil Qty Card Set
Neck Breaker Shadows over Innistrad
Ancient of the Equinox Shadows over Innistrad
Krallenhorde Howler Shadows over Innistrad
Ormendahl, Profane Prince Shadows over Innistrad

can u please help and let me know how to fix this

Got it to work just deleted those lines in notepad

To answer your question (albeit late), the error is being displayed because those are the back side of flip cards and therefore don't have their own database entry.