With Tiny's help and I am able to get oFollow working in WOD 6.0.3. Thanks for Tiny again for the wonderful support.
The issue appears that I had different movement key-binds from the default settings. Basically, in order to let oFollow work smoothly with any version of WOW (retail, private servers, etc), you need to have the arrow keys with default movements assigned to all your boxing toons:
1. Forward -> Up Arrow
2. Backward -> Down Arrow
3. Turn Left -> Left Arrow
4. Turn right -> Right Arrow
BTW, I would like to bring up some other notes for people who are interesting in oFollow:
1. Does oFollow work for the open world in WOW besides Battle Grounds?
Ans: Yes, with a little extra oFollow command: "/of debug on" on all your boxing toons, and this will enable you to use oFollow in the open world. oFollow is mainly designed for the boxers who want to do boxing in Battle Grounds after Blizzard's "/follow" nerfed. This is pretty good for testing before you get owned in BGs if you didn't set it up correctly. By issuing "/of debug off" on all your boxing toons, the debug mode is set to off.
2. Does oFollow work with multiboxing software, such as ISBoxer?
Ans: Yes, I am using ISBoxer and I can confirm that oFollow has zero conflict with ISBoxer. Note: You have to configure oFollow dimension precisely with your ISBoxer's windows layouts. For example, if you configure your ISboxer: main Windows Slot is 1280 x 960 and rest of Windows Slot is 480 x 240, you have to use "/of" to configure your oFollow's dimension: master - 1280 x 960; slave - 480 x 240.