mounting administrative xp share via smbfs on 5.4

[dave]

Hello,
    I've got a freebsd 5.4 box that i'm trying to mount the C$
administrative share from a windows xpsp2 professional box. Using
smbclient -L comp2 shows the box and the c$ share, however,
mount_smbfs -I comp2 //user at comp2/c$ /mnt
produces an error: operation not permitted. The share itself as far as i
know does not have a password.
Thanks.
Dave.