App Engine - Struts2 - The Struts dispatcher cannot be found

I'm writing an app using Struts2 and Google App engine. When I run the application locally, everything goes smoothly. But, when I upload the application (Using Eclipse Google plug-in) and try to access it through web, I'm getting 500 server error. In the app engine log files, I could see below error message:

The St开发者_开发百科ruts dispatcher cannot be found. This is usually caused by using Struts tags without the associated filter. Struts tags are only usable when the request has passed through its servlet filter, which initializes the Struts dispatcher needed for this tag. - [unknown location]

What I'm wondering is, same app works perfectly when run locally but fails when deployed on App Engine.

1. Is it because the struts2 JAR files are not uploaded along with other files? (I have placed the JAR files inside WEB-INF/lib. So ideally the JAR files should get uploaded).
2. Is there any specific configuration that I have to make before uploading the struts2 app to app engine?