Domain Mapping - permalink does not work

Hi,

Good day. After successfully configured the domain mapping pluggin with my wp multisite 3.0, I found that all the permalink no longer work if I map a domain to existing site, for instance:

Before:

[works] abc.mysite.com/about/
[works] abc.mysite.com/wp-login.php

After:

[no longer works] blog.mynewsite.com/about/
[works] blog.mynewsite.com/wp-login.php

This happens to other post permalinks as well. May I know what am I missing here?