With a custom plugin deployed, I'm getting the following error message and the webapp doesn't start:
validateJarFile(E:\6.1\liferay-portal-tomcat-6.1.1-ce-ga2-20120731132656558\liferay-portal-6.1.1-ce-ga2\tomcat-7.0.27\temp\4-SiteSkills_CMS-portlet\WEB-INF\lib\javax.servlet-api-3.0.1.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class
Why and how can I get rid of this message?