My Portlet name is Sample-ext so I am referring with this name in the below steps :-

1) Stop the Server
2) put ext-redeploy-6.0.5.jar in tomcat-6.0.29/Webapps/ROOT/WEB-INF/lib/
3) Delete the Sample-ext portlet from the webapps folder if in case you are redeploying
4) Remove ext-Sample-ext-service.jar from the tomcat-6.0.29\lib\ext
5) Remove all the *-ext.xml from the path tomcat-6.0.29\webapps\ROOT\WEB-INF except struts-config-ext.xml
6) Remove all the jar file related to ext from the tomcat-6.0.29\webapps\ROOT\WEB-INF\lib except ext-redeploy-6.0.5.jar
7) Start the Server
8) Deploy the EXT Portlet
9) After that it will ask for rebooting the server once the EXT portlet is successfully deployed.
10) Now once again start the server.

Your EXT portlet will re-deployed successfully and all the changes will get Executed.

Hope it helps !!!