AFP connect as root.

Heffalump runs leopard. Owl runs tiger. Both are up to date re: security patches. Both have user System Adminsitrator (root) enabled. We're trying to run Sync as root from heffalump to owl. As user laura we can connect to Owl with no problems. As user root, I cannot connect from Heffalump to Owl. I get 'username or password is incorrect.' Looking on other forums afp seems to be a bit shaky between OS versions. Can anyone direct me to clues?