How to use mkntfs, I get "not a block device"

[Thomas Mueller]

I can't format a partition for NTFS with fusefs-ntfs port, using mkntfs.

Error message is

root at amelia:~ # mkntfs /dev/gpt/SeaExp1-03                                      
/dev/gpt/SeaExp1-03 is not a block device.                                      
Refusing to make a filesystem here!    

This doesn't happen with filesystems supported by the base system (UFS, FAT32).

I was able to mount an NTFS partition read-write after "kldload fuse", so I did "kldload fuse" here, but that didn't work for mkntfs.

I noticed that typing mount by itself showed the mounted NTFS partition as /dev/fuse, but for mkntfs, I don't have anything mounted.

I believe one can only mount an already-existing filesystem, so what to do for mkntfs?

As I type this message, something strange has happened: key with apostrophe (unshifted) and double quotes (upshift) has gone dead, don't know if the keyboard (PS/2, dating to July 2001), or if some quirk has happened with this FreeBSD-current amd64 system, will try rebooting into FreeDOS or NetBSD, or even starting X.

uname -a shows

FreeBSD amelia 11.0-CURRENT FreeBSD 11.0-CURRENT #3 r278021: Mon Feb  2 04:18:13 UTC 2015     root at amelia:/usr/obj/usr/src/sys/SANDY11NC  amd64

I create the apostrophe and double quote by the old trick Alt-039 and Alt-034.  If necessary, I have USB keyboard to switch to on reboot.

Tom