Problem with mount_ntfs

[Vladimir Yourtaev]

Hello all
My system FreeBSD-4.9 REALEASE
kernel compiled with options NTFS 
hard ad0 has 3 partition: 
ad0s1 -Primary NTFS;
ad0s2 -Extended NTFS;
ad0s3 - Primary FreeBSD;
When I try from to mount ntfs partition via commands: mount_ntfs /dev/ad0s1 /
mnt or mount -t ntfs /dev/ad0s1 /mnt  I get a messege:
< mount_ntfs: vfsload(ntfs): File exists >
What does this mean, and what i'll do next? How I can to get access to NTFS 
partition my hard drive?