Java EE (Java Enterprise Edition) General Discussion

From one of the forum posting, i read that the classpath is missing servlet.jar.
I have a build.xml that points to the path of servlet-api.jar.
I am running the build before i start tomcat.

But when i try to run tomcat through eclipse (using sysdeo), I get the above error.
Can someone give pointers what am i doing wrong & how this can be fixed?

INFO: XML validation disabled
[DevLoader] Starting DevLoader
[DevLoader] JSPCompiler Classpath = /home/username/apache-tomcat-5.5.15/webapps/username/WEB-INF/classes/:
/home/username/apache-tomcat-5.5.15/bin/bootstrap.jar:
/usr/local/java/jdk1.5.0_06/jre/lib/ext/sunjce_provider.jar:
/usr/local/java/jdk1.5.0_06/jre/lib/ext/sunpkcs11.jar:
/usr/local/java/jdk1.5.0_06/jre/lib/ext/dnsns.jar:
/usr/local/java/jdk1.5.0_06/jre/lib/ext/localedata.jar:
java.lang.reflect.InvocationTargetException

Caused by: java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet