[BusyBox] Loopback device setup?

[Tom Guilliams]

I'm using Busybox version 1.00-pre2 and can't seem to mount a loopback 
device.  I'm get the following info when I use "mount" or "losetup". 
Any ideas what I'm doing wrong?  "ramdisk.image" is an image I created 
with mke2fs I built in.

/tmp # mount -t ext2 -o loop ramdisk.image rootfs
mount: ioctl: LOOP_SET_FD: Invalid argument
mount: Could not setup loop device
/tmp # losetup /dev/loop0 ramdisk.image
losetup: ioctl: LOOP_SET_FD: Invalid argument
/tmp #

Thanks in advance,

Tom