Hi Lane,
Thanks for the updates in the private message and glad to see the issue is resolved.
We eventually solve the issue by uninstalling the old version of DirSync and install the new version of Windows Azure Active Directory Sync tool by referring to: http://blogs.technet.com/b/canitpro/archive/2014/09/30/step-by-step-setting-up-the-new-aad-sync.aspx, in case others who happens to have the similar issue may want to find the solution.