Problem compiling new RapidMiner class (added to main RapidMiner project)

I want event (update) listeners on my ExampleSets.  I want to log / process real-time data in RM and I think the best way to do this is to add an EventUpdateListener to ExampleSet which then registers the event listener with the underlying MemoryTable.  Whenever MemoryTable add or remove methods are called, MemoryTable notifies the registered listener objects.  In order to do this, I had to create an EventListener interface which I put in the path: com.rapidminer.example.table.TableUpdateListener.

When I run the RM_Extension compile script which came with the developer guide, I get this error:

Buildfile: /home/boxer/workspace/RM_Extension/build.xml
clean:
     [echo] Cleaning...
   [delete] Deleting directory /home/boxer/workspace/RM_Extension/build
   [delete] Deleting directory /home/boxer/workspace/RM_Extension/javadoc
    [mkdir] Created dir: /home/boxer/workspace/RM_Extension/build
    [mkdir] Created dir: /home/boxer/workspace/RM_Extension/javadoc
version.get:
version.updateFiles:
init.setEncoding:
init:
init.setEncoding:
Trying to override old definition of task get
Trying to override old definition of task post
copy-resources:
     [echo] Copying resources...
     [copy] Copying 11 files to /home/boxer/workspace/RM_Extension/build
build:
Trying to override old definition of task post
build.rm:
Trying to override old definition of task post
build.dependent:
     [echo] RapidMiner Extension: Compile with Java from dir: /usr/lib/jvm/java-6-sun-1.6.0.20/jre
     [echo] RapidMiner Extension: using Java version: 1.6.0_20
    [javac] Compiling 310 source files to /home/boxer/workspace/RM_Extension/build
    [javac] warning: [path] bad path element "/home/boxer/workspace/RapidMiner_Vega/lib/jdbc/jcifs.jar": no such file or directory
    [javac] /home/boxer/workspace/RM_Extension/src/com/rapidminer/operator/realtime/debug/Receiver.java:7: cannot find symbol
    [javac] symbol  : class TableUpdateListener
    [javac] location: package com.rapidminer.example.table
    [javac] import com.rapidminer.example.table.TableUpdateListener;
    [javac]                                    ^

What do I need to do to fix this?  Seems that the extension does not use the source directories, but rather links to libraries.  I'd like to avoid the RM_Extension build script if possible.  I don't plan to redistribute these operators and it's annoying to have to recompile / bundle JAR files every time I make a change.  Is there a way I can just simply have them compiled into the main RM project?  Also, does RM have a table event update listener built-in already for ExampleSet that I missed?  I know RM is not really intended for real-time processing (or at least I assume as my previous question about RM real-time application went unanswered), but it seems like it would be easy to extend it for that purpose.