Hello i searched for many solutions and tried them, now if got a new error which i do not understand at all. The main problem is that the Portlet does not run and the Console tells us that the portlet started but look for yourself:
INFO: Deploying web application directory opensocial-portlet
INFO [main] (WebApplication.java:757) - [OntopolyApplication] Started Wicket version 1.4.15 in deployment mode
08:21:50,949 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
Loading file:/C:/liferay-portal-6.0.6/tomcat-6.0.29/webapps/opensocial-portlet/WEB-INF/classes/service.properties
08:21:51,075 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:54,359 INFO [PortletHotDeployListener:220] Registering portlets for opensocial-portlet
08:21:54,361 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:54,372 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:54,441 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:54,458 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
Loading file:/C:/liferay-portal-6.0.6/tomcat-6.0.29/webapps/opensocial-portlet/WEB-INF/classes/portlet.properties
08:21:54,471 INFO [PortletHotDeployListener:374] 2 portlets for opensocial-portlet are available for use
Loading file:/C:/liferay-portal-6.0.6/tomcat-6.0.29/webapps/opensocial-portlet/WEB-INF/classes/service.properties
08:21:54,588 INFO [DialectDetector:69] Determining dialect for HSQL Database Engine 1
08:21:54,589 WARN [DialectDetector:84] Liferay is configured to use Hypersonic as its database. Do NOT use Hypersonic in production. Hypersonic is an embedded database useful for development and demo'ing purposes. The database settings can be changed in portal.properties.
08:21:54,589 INFO [DialectDetector:49] Using dialect org.hibernate.dialect.HSQLDialect
Loading file:/C:/liferay-portal-6.0.6/tomcat-6.0.29/webapps/opensocial-portlet/WEB-INF/classes/service.properties
08.11.2011 08:21:57 org.apache.catalina.core.StandardContext start
SCHWERWIEGEND: Error listenerStart
08.11.2011 08:21:57 org.apache.catalina.core.StandardContext start
SCHWERWIEGEND: Context [/opensocial-portlet] startup failed due to previous errors
08:21:57,586 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:57,591 WARN [SAXReaderImpl:429] XSD validation is diasabled because org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration
08:21:57,610 INFO [ExtHotDeployListener:205] Extension environment for opensocial-portlet will not be undeployed
08:21:57,611 INFO [PortletHotDeployListener:404] Unregistering portlets for opensocial-portlet
08:21:57,614 INFO [PortletHotDeployListener:440] 2 portlets for opensocial-portlet was unregistered
08.11.2011 08:21:57 org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SCHWERWIEGEND: The web application [/opensocial-portlet] appears to have started a thread named [com.google.inject.internal.Finalizer] but has failed to stop it. This is very likely to create a memory leak.
08.11.2011 08:21:57 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SCHWERWIEGEND: The web application [/opensocial-portlet] created a ThreadLocal with key of type [null] (value [org.apache.shindig.common.xml.XmlUtil$2@47370e]) and a value of type [org.apache.xerces.jaxp.DocumentBuilderImpl] (value [org.apache.xerces.jaxp.DocumentBuilderImpl@16f7e6e]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
08.11.2011 08:21:57 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
SCHWERWIEGEND: The web application [/opensocial-portlet] created a ThreadLocal with key of type [null] (value [com.google.inject.InjectorImpl$1@d573c7]) and a value of type [java.lang.Object[]] (value [[Ljava.lang.Object;@1a41a8d]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
08.11.2011 08:21:57 org.apache.catalina.startup.HostConfig deployDirectory
Thank you for your answers.
I know my response is late but I have hit my head on this problem for the last day and finally, I found the source of my problem :
Basically, I had gwt-dev.jar and gwt-user.jar in my tomcat/lib/ext. When starting my server, I had the following warning making my portal not starting up correctly.
By removing my jars from the tomcat/lib/ext removed the warning and my portal started propertly.
If you need the jars, deploy them in your portlet.