Tomcat NoClassDefFoundError + LifecycleException

[Dar Var]

I am trying to hot deploy to Borland Enterprise Server so I have turned on the per_module class loading policy for the server to allow this. However I get two exceptions:

1.java.lang.NoClassDefFoundError:
2.LifecycleException: -container for web app doesn't start

and a Tomcat problem back when I try to retrieve my login page
Borland-Apache Tomcat/4.0.3 - HTTP Status 500 - No Context configured to process this request

I think this is a class loading problem with Tomcat but I don't know how to resolve it.

[Ray Stojonic]

This problem builds on itself:

1 - the class can't be found, so
2 - the lifecycle of the context cannot start, so
3 - the context is not available, so
4 - you get a 500 error

What class does it say it cannot find?

Where did you reference that class?

Have you placed the class where you told tomcat you would place it?

If the class in question is in a .jar, have you placed the jar in either:
CATALINA_HOME/common/lib, CATALINA_HOME/shared/lib, or <your context>/WEB-INF/lib?