Mounting XP drive

[Rem P Roberti]

I've been having trouble mounting a Windows XP drive.  Acutally, the 
drive mounts, but the system always starts up in single user mode.  Here 
is the fstab:

# Device                Mountpoint      FStype  Options         Dump    
Pass#
/dev/ad0s1b             none            swap    sw              0       0
/dev/ad0s1a             /               ufs     rw              1       1
/dev/ad0s1d             /usr            ufs     rw              2       2
/dev/ad1s1              /c              ntfs    rw              1       1
/dev/acd0               /cdrom          cd9660  ro,noauto       0       0

When I try to boot the system I get this error message:

fsck: exec fsck_ntfs for /dev/ad1s1 in /sbin:/usr/sbin: no such file or 
directory

The system then goes directly into single user mode.  When I ctrl-D my 
way into multi-user mode and do a df I find that the Windows drive is 
mounted.  I just can't seem to avoid the initial boot into single-user 
mode.

Any help would be appreciated.

Rem