Tokens
Tokens will need to be renamed to not include "Token". In Deckbox, it's just "Bird", not "Bird Token".
Ensure the Edition column for all tokens includes the correct "Extras" edition. You'll have to change it for all tokens, since TCGplayer doesn't use a separate edition for them.
So instead of
Bird Token -- # T1 -- Khans of Tarkir
Deckbox uses
Bird -- # 1 -- Extras: Khans of Tarkir
NOTE: Some precon editions have the tokens listed in the main edition numbering, and NOT in an Extras edition. E.g. Duel Decks: Speed v Cunning through DD: Nissa v Nixilis.
Editions
As to unrecognized edition names, just check the Editions page for the Deckbox version of the Edition name. In the case of MM2017, you'd change it from "Modern Masters 2017" to "... 2017 Edition". Use the Find & Replace All functionality of whatever program you're editing the CSV in.
Other Columns
And re: the Set Code column.... It's a little unclear from your post whether this column is generating an actual error during import, or whether it's just being ignored. Regardless, you can safely delete the column, as Deckbox doesn't use it.
On the opposite side of things, you may want to add two columns prior to import -- Condition and Language. Their absence won't cause the import to fail, but you also won't get your default condition and language applied to the cards. They'll be listed in your inventory seemingly without a condition or language. (This may be fine with you if you're not tracking condition. Or you could mass-apply "Near Mint" or "Good (Lightly Played".)