I use this to mount NTFS all the time. Possibly you have multiple partitions on these disks. You have to mount a specific partition. Is there a '+' icon next to the drives that would let you expand to see the partitions? Maybe post a screenshot showing what you are talking about.
here's a screenshot http://i.imgur.com/64mcHGn.png
There are 3 partitions on each of the drives. I can get the format button to enable if I turn on the destructive setting but that's not helpful.
As for the log, it contains nothing but the same error John_M is talking about, a new entry every 2 seconds. These are devices that were initially formatted in Windows 10, but not OS drives.
EDIT: I gave up and just added them to the array, none of the data lost was replaceable and I wanted to move on.