ClassNotFoundException when using the XML-RPC client

Following the instructions on http://continuum.apache.org/docs/1.3.1/developer_guides/xmlrpc.html results in:

[INFO] Exception in thread "main" org.apache.xmlrpc.XmlRpcException: Failed to invoke method getAllProjectGroups in class org.apache.maven.continuum.xmlrpc.server.ContinuumServiceImpl: java.lang.ClassNotFoundException: org.apache.maven.continuum.buildqueue.BuildProjectTask
[INFO] at org.apache.xmlrpc.client.XmlRpcStreamTransport.readResponse(XmlRpcStreamTransport.java:186)
[INFO] at org.apache.xmlrpc.client.XmlRpcStreamTransport.sendRequest(XmlRpcStreamTransport.java:145)
[INFO] at org.apache.xmlrpc.client.XmlRpcHttpTransport.sendRequest(XmlRpcHttpTransport.java:94)
[INFO] at org.apache.xmlrpc.client.XmlRpcSunHttpTransport.sendRequest(XmlRpcSunHttpTransport.java:44)
[INFO] at org.apache.xmlrpc.client.XmlRpcClientWorker.execute(XmlRpcClientWorker.java:53)
[INFO] at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:166)
[INFO] at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:136)
[INFO] at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:125)
[INFO] at org.apache.xmlrpc.client.util.ClientFactory$1.invoke(ClientFactory.java:132)
[INFO] at $Proxy0.getAllProjectGroups(Unknown Source)
[INFO] at org.apache.maven.continuum.xmlrpc.client.ContinuumXmlRpcClient.getAllProjectGroups(ContinuumXmlRpcClient.java:173)
[INFO] at net.wsmoak.continuum.App.main(App.java:44)

SampleClient.java on trunk gives similar results. To reproduce:

1. cd /path/to/continuum/continuum-xmlrpc/continuum-xmlrpc-client
1a. edit url/userid/password in pom.xml if necessary
2. mvn exec:exec

We don't have a org.apache.maven.continuum.buildqueue.BuildProjectTask class as far as I can tell. Should it be org.apache.continuum.taskqueue.BuildProjectTask instead?