What might help (it helped me while trying to load images from my 
Linux-box to VXT's):
Make all arp and rarp entries on your server permanent; then, the VAX 
doesn't have to answer (r)arp-request.
How to do that? In your /etc/inittab:

a:23:once:/usr/sbin/arp -f /etc/ethers
r:23:once:/usr/local/bin/setup_rarp

/etc/ethers looks like:

kenkeni 08:00:2B:2C:3B:96
vaxie   08:00:2B:2C:D1:86
nettie  08:00:2B:33:E9:91

/usr/local/bin/setup_rarp looks like:

#!/bin/sh
while read h a
do /usr/sbin/rarp -s $h $a
done < /etc/ethers

Hope this helps!
Hans.