Hi Tang,
I've started getting reports about extension problems:
http://groups.google.com/group/new-tab-jumpstart/t/8bc6186e96e1ca90?hl=en
I'll be investigating it immediately, however if you want to help
please read the instructions I left in the above thread and send me
the details if possible.
And all communication should be done on the above thread.
Thanks,
Mihailo