rsync on ultrix

[glen]

I have a machine running Ultrix V4.4 (which I hate).

I just compiled and installed rsync v 2.3.1 (the same version
I use elsewhere)

Can anyone explain why 

rsync -aux /usr/ remote_machine:/destination/usr

works, but

rsync -aux / remote_machine:/destination/rfs

fails (looks like it's doing something, but just hangs
indefinitely)?

Or, how I SHOULD do this?

thanks for any help. :)
-- 
Glen Davison                    [EMAIL PROTECTED]
Computer System Administrator   phone: +61 2 9385 7018
Maths, UNSW                     fax:   +61 2 9385 7123