Hadoop 0.20.1 - Null pointer exception on startup

I am trying out Hadoop on my Mac0SX (10.5.8). I unzipped the distribution and after cd'ing to ~/hadoop-0.20.1/bin, ran

ashee-mac:bin amitava$ ./start-all.sh

I get the following exception

2010-01-20 13:14:13,341 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: STARTUP_MSG: 
/************************************************************
STARTUP_MSG: Starting NameNode
STARTUP_MSG:   host = ashee-mac/10.17.8.21
STARTUP_MSG:   args = []
STARTUP_MSG:   version = 0.20.1
STARTUP_MSG:   build = http://svn.apache.org/repos/asf/hadoop/common/tags/release-0.20.1-rc1 -r 810220; compiled by 'oom' on Tue Sep  1 20:55:56 UTC 2009
************************************************************/
2010-01-20 13:14:13,480 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: java.lang.NullPointerException
 at org.apache.hadoop.net.NetUtils.createSocketAddr(NetUtils.java:134)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.getAddress(NameNode.java:156)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.getAddress(NameNode.java:160)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:175)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:279)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:956)
 at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:965)

2010-01-20 13:14:13,482 INFO org.apache.hadoop.hdfs.server.namenode.NameNode: SHUTDOWN_MSG: 
/************************************************************

---

Turns out, the default does not come configured with, well "defaults". The fix is easy enough as highlighted in Quick Start (duh)

conf/core-site.xml:

<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
</configuration>

conf/hdfs-site.xml:

<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
</configuration>

conf/mapred-site.xml:

<configuration>
<property>
<name>mapred.job.tracker</name>
<value>localhost:9001</value>
</property>
</configuration>