This is a situation where you need to edit the CSV file.
My suggestions are:
Save the CSV file and open it using windows notepad and compare it with /block eXport entry from your books (MC account target account) and note the differences to import using /Block Import.
Another alternative is run the procedure EXPTRANS on a transaction from the MC account and file compare the CSV file with the file created with EXPTRANS and match the file syntax to use with the procedure IMPORT.
I hope this helps.
Regards to All,