Check your web.xml, probably there's some misconfiguration.
Thanks for the suggestion. It seems not related to the web.xml, since all the projectes used to work all having problem. Today I tested Firefox (most time I use IE), which worked fine (server does not throw excepion). After spend many hours, finally I made things working again: clean all IE history but the trick is, also empty the recycle bin.
I read some where that this was a bug in Richface old release, but I am using version 3.3.1, seems the bug not totally fixed.