This line:
class file has wrong version 49.0, should be 48.0 suggests that you are mixing different versions of Java - versions 1.4 and 1.5. Make sure that you are running
Tomcat on Java 1.5 and that it uses JDK 1.5 to compile the JSP's. Right now, it looks like Tomcat is using JDK 1.4 to compile the JSP's.
Which version of Tomcat are you using? I think the newest versions of Tomcat require Java 1.5 (check the Tomcat documentation), are you trying to run it on Java 1.4?