Certifique-se de adicionar seu ojdbc7.jar ao seu classpath.
1.Add ojdbc7.jar to TOMCAT_HOME/lib
2.Add ojdbc7.jar to JAVA_HOME/jre/lib
3.Trying with ojdbc6.jar if it still not works
1.Add ojdbc7.jar to TOMCAT_HOME/lib
2.Add ojdbc7.jar to JAVA_HOME/jre/lib
3.Trying with ojdbc6.jar if it still not works
