I'm having this problem, too...running v9.3 stable and trying to import a NTFS drive. I manually created a directory via shell under the MNT directory called "Share"...I clicked import disk...selected disk...selected type...browsed to "/mnt/Share" (this is what shows in the box below the error message) and clicked "Import Volume". I don't understand how this can be an issue...
Ok...this seemed counterintuitive, because it felt like I was trying to mount a drive inside another drive's mount point. I had read the linked document, but totally missed the line at the top that said "The import is meant to be a temporary measure in order to copy the data from a disk to an existing ZFS dataset."
However...now it's been sitting at the Import Disk progress bar for an hour...there wasn't much data on this drive. It was mostly just a test drive formatted NTFS with a few files to make sure it would work before I went farther...
These are all sata drives...I'll check /var/log/messages tonight.
I see the files appearing in my volume after doing the import disk, but I don't know if they're copying or what (no progress bar...no status...other than the window I told to run in the background since it didn't seem to be doing anything other than show something was happening). I last checked Saturday and directories and files seem to be appearing, but last video file I tried to run remotely told me there was an error opening the file. I figured it is just making placeholders or still copying or something.
Update: I let it run for two days doing whatever it is it was doing when I imported the disk. I can now access the files via CIFS, but did importing the disk copy the files to my ZFS volume or is it doing some sort of directory combining? If it was a copy, how can I verify all my files were moved over?
I did a size compare from drive to drive and it looked complete. I didn't see anywhere in the import document where it said what it was doing (I thought it was just going to mount the drive and I'd copy the files over manually). I didn't get an email from FreeNAS that the copy was complete or any sort of status message that I saw, but it looks like it was complete. I set my second drive copying before bed last night.
Thanks for the help, everyone...I'm willing to bet other people getting this error are also thinking that the import is mounting the drive and trying to do what I did (make a mount directory and point it there).