Today, I have switched back from sping 1.2.8 to sping 2.0 and somehow, the problem is gone and it works. I think it may be caused by unstable Tomcat 5.5.20, which I have used as my server or my unstable eclipse3.2 since I deploy and run Tomcat inside my eclipse.

So far, I have used following jar files:
xfire-all-1.2.2.jar; xbean-spring-2.7.jar; xbean-2.1.0.jar ... etc.