NullPointer when attempting to list targets

[david@localhost bin]$ ./windup --updateRulesets
Using Windup at /home/david/RHN/jboss-migrationtoolkit-windup-2.4.0.GA
Warning: JAVA_HOME environment variable is not set.
Core rulesets: Installed: 2.5.0.Final Latest release: 2.5.0.Final
Checking for rulesets updates...
Core rulesets: Installed: 2.5.0.Final Latest release: 2.5.0.Final
[david@localhost bin]$ ./windup --listTargetTechnologies
Using Windup at /home/david/RHN/jboss-migrationtoolkit-windup-2.4.0.GA
Warning: JAVA_HOME environment variable is not set.
Core rulesets: Installed: 2.5.0.Final Latest release: 2.5.0.Final
Writing graph config to /tmp/windupgraph_NQEsJt/TitanConfiguration.properties
Windup execution failed due to: null
java.lang.NullPointerException
at org.jboss.windup.config.metadata.RuleProviderRegistryCache.getAvailableTargetTechnologies(RuleProviderRegistryCache.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.jboss.forge.furnace.proxy.ClassLoaderInterceptor$1.call(ClassLoaderInterceptor.java:87)
at org.jboss.forge.furnace.util.ClassLoaders.executeIn(ClassLoaders.java:42)
at org.jboss.forge.furnace.proxy.ClassLoaderInterceptor.invoke(ClassLoaderInterceptor.java:103)
at org.jboss.windup.config.metadata.RuleProviderRegistryCache_$$javassist_8df702d1-6631-4ae7-8727-922bc8f562a1.getAvailableTargetTechnologies(RuleProviderRegistryCache$$_javassist_8df702d1-6631-4ae7-8727-922bc8f562a1.java)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.jboss.forge.furnace.proxy.ClassLoaderAdapterCallback$2.call(ClassLoaderAdapterCallback.java:123)
at org.jboss.forge.furnace.util.ClassLoaders.executeIn(ClassLoaders.java:42)
at org.jboss.forge.furnace.proxy.ClassLoaderAdapterCallback.invoke(ClassLoaderAdapterCallback.java:96)
at org.jboss.windup.config.metadata.RuleProviderRegistryCache_$$javassist_5a85b4b8-f1d2-4e4a-92c4-0d2133257559.getAvailableTargetTechnologies(RuleProviderRegistryCache$$_javassist_5a85b4b8-f1d2-4e4a-92c4-0d2133257559.java)
at org.jboss.windup.bootstrap.commands.windup.ListTargetTechnologiesCommand.execute(ListTargetTechnologiesCommand.java:19)
at org.jboss.windup.bootstrap.Bootstrap.executePhase(Bootstrap.java:286)
at org.jboss.windup.bootstrap.Bootstrap.run(Bootstrap.java:160)
at org.jboss.windup.bootstrap.Bootstrap.main(Bootstrap.java:95)