Having Trouble Deploying JRuby on Rails app to Tomcat 6

I'm developing a JRuby on Rails app using netbeans 6.1. I'm trying to deploy to Tomcat 6.  I've installed warbler as a plugin, and it's generated my WAR file.  I copied it to $TOMCAT_HOME/webapps and I can access it in my browser at http://localhost:8084/$YOUR_APP_NAME just fine.  However, none of my images show on the page, and after doing some research on Google, it's clear that my app needs to run as the root webapp in Tomcat because of some of the logic used by the rails asset tags. 

This is my first time using Tomcat, so I'm not quite sure how to configure Tomcat to make my app run as the root.  Googling the topic gave me several things to try (e.g. renaming my war as ROOT.war and removing the existing ROOT webapp; creating a ROOT.xml file in $CATALINA_HOME/conf/[enginename]/[hostname]/ with a docBase element pointing to my war file), but none of these are working.  In each case, I get a java.lang.OutOfMemoryError.  Here's the stack trace:

Jun 10, 2008 2:25:30 PM org.apache.catalina.core.ApplicationContext log
SEVERE: Exception caught
org.jruby.rack.RackInitializationException: IO error -- builtin/java/exceptions
    from file:/C:/Users/Myron/.netbeans/6.1/apache-tomcat-6.0.16_base/webapps/ROOT/WEB-INF/lib/jruby-complete-1.1.2.jar!/META-INF/jruby.home/lib/ruby/site_ruby/1.8/builtin/javasupport.rb:47:in `file:/C:/Users/Myron/.netbeans/6.1/apache-tomcat-6.0.16_base/webapps/ROOT/WEB-INF/lib/jruby-complete-1.1.2.jar!/META-INF/jruby.home/lib/ruby/site_ruby/1.8/builtin/javasupport.rb'
    from file:/C:/Users/Myron/.netbeans/6.1/apache-tomcat-6.0.16_base/webapps/ROOT/WEB-INF/lib/jruby-complete-1.1.2.jar!/META-INF/jruby.home/lib/ruby/site_ruby/1.8/builtin/javasupport.rb:1

    at org.jruby.rack.DefaultRackApplicationFactory.newRuntime(DefaultRackApplicationFactory.java:85)
    at org.jruby.rack.DefaultRackApplicationFactory.createApplication(DefaultRackApplicationFactory.java:144)
    at org.jruby.rack.DefaultRackApplicationFactory.newApplication(DefaultRackApplicationFactory.java:44)
    at org.jruby.rack.DefaultRackApplicationFactory.getApplication(DefaultRackApplicationFactory.java:52)
    at org.jruby.rack.PoolingRackApplicationFactory.getApplication(PoolingRackApplicationFactory.java:92)
    at org.jruby.rack.DefaultRackDispatcher.process(DefaultRackDispatcher.java:31)
    at org.jruby.rack.RackFilter.doFilter(RackFilter.java:51)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:196)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:619)
Caused by: org.jruby.exceptions.RaiseException: IO error -- builtin/java/exceptions
Caused by: java.lang.OutOfMemoryError: Java heap space

Not sure if this helps, but here's my environment:
Windows Vista
MySQL 5
Netbeans 6.1
Rails 2.1
JRuby 1.1.2
Tomcat 6.0.16

Anyone know how to get this to work?

Thanks,
Myron