SEVERE: Context [/twitter] startup failed due to previous errors

When I deploy twitter portlet in my Liferay Portal, it seems working fine. But in my Activities portlet, there're no activities shown when I tweet in Twitter. Searched online, tried all solutions but still doesn't work. So I create my own twitter portlet based on Twitter portlet source code. It's built by using service builder.

When I deploy the project, it tells me can't register twitter portlet properly without any error information.

WARNING: [SetContextPropertiesRule]{Context} Setting property 'source' to 'org.eclipse.jst.jee.server:twitter' did not find a matching property.
Nov 9, 2012 7:21:15 PM org.apache.catalina.core.StandardContext listenerStart

Nov 9, 2012 7:21:15 PM org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/twitter] startup failed due to previous errors

How could I figure it out? The issue is we need to find out where causes the start problem. We need to see the detail log. Unfortunately by default, tomcat won't provide any details about the cause of the error. We can config it by ourselves. In our WEB-INF/src, we can create a logging.properties file with the following contents:

org.apache.catalina.core.ContainerBase.[Catalina].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].handlers = java.util.logging.ConsoleHandler

In this case, Tomcat will show me error details.