Hello Yikun,
I also work with CW5.1. and the MC9s12c128
Before I use CW5.1 with windows XP and after loading Windows 10 CW5.1 didn't worked anymore.
If you use the USBDM to load a target, you have to reload the latest USBDM files according to your computer from the "sourceforge" website.
I loaded the 4.12.1.200 and everything works again.
It could be possible that you first have to remove the current USBDM file on your computer before loading a new one.
http://sourceforge.net/projects/usbdm/files/Version%4.12.1.200/Software
Hope it works for you
Bye HuDo