udpcast with --file switch

I have successfully been using boot media of udpcast from
http://udpcast.linux.lu/ to image physical disk drives to other physical
disk drives. I would like to also be able to image a physical disk
drive or partition to an image *file* on another larger drive, so I can
have a number of different images for re-installation on student
workstations in a classroom. So far no success with the --file switch.

I have tried launching udp-receiver on a running system and directing
the output to a file as described in the man pages as follows:
udp-receiver --file <filename on a mounted partition>
The udp-sender running from a udpcast boot cd on the machine to be
imaged and the udp-receiver on the running Linux system see and
recognize each other, and when I "Press a key" to start the transfer,
udp-sender tries to send. The udp-receiver just sits there, and the
udp-sender spews multiple timeout messages on its screen. I then kill
the udp-receiver process and reboot the udp-sender machine.

An empty file of <filename on a mounted partition> is created but it has
zero bytes in it. I keep thinking there's another command switch I'm
overlooking, at least I hope that's all it is.

I need help with this.

Thanks,
Mark