Successfully rooted DHD using AAHK, thanks!
Thanks for the great help from the development team and those from the AAHKsupport IRC, espcially attn1, Zanzibar and many others.
Originally I tried to use ubuntu live CD to run the hack environment but it failed trying to chmod hack-ace.sh to 755. I gave up after few times of downloading, unzipping, logging in as root, etc.
Then I ran the hack kit from the Win 7 environment, luckily I didn't have Apple / iPhone stuff installed on that machine. After removing the HTC Sync, antivirus and adware programs from the PC, I ran the windows version of the hack kit.
The whole process is so smooth that it took 8 minutes from "pressing 1" to finish. During the process, there is nothing I need to interfere and all data and apps are intact as before.
Now it is time for me to learn how to install custom rom and hopefully try out the full functionality of this DHD.
AAHK and other contributors, great job!