Arc to segements failed for " Task attempt_200907091108_0001_m_000520_0 failed to report status for 602 seconds. Killing!"

hi, I try to convert arc file to segments these days ,  nutch goes well for
convert 2millions pages,but for it failed for " Task
attempt_200907091108_0001_m_000520_0 failed to report status for 602
seconds. Killing!" when i increase the page counter to 7 millions, I have 10
nodes. for  the hadoop-site.xml config as below:
Any hlep would appreciate..
==============================================================
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
  <name>fs.default.name</name>
  <value>hdfs://distributed1:9000/</value>
  <description>The name of the default file system. Either the literal
string "local" or a host:port for DFS.</description>
</property>
<property>
  <name>mapred.job.tracker</name>
  <value>distributed1:9001</value>
  <description>The host and port that the MapReduce job tracker runs at. If
"local", then jobs are run in-process as a single map and reduce
task.</description>
</property>
<property>
  <name>hadoop.tmp.dir</name>
  <value>/home/had/nutch-1.0/tmp</value>
  <description>A base for other temporary directories.</description>
</property>
<property>
  <name>dfs.name.dir</name>
  <value>/home/had/nutch-1.0/filesystem/name</value>
  <description>Determines where on the local filesystem the DFS name node
should store the name table. If this is a comma-delimited list of
directories then the name table is replicated in all of the directories, for
redundancy. </description>
</property>
<property>
  <name>dfs.data.dir</name>
  <value>/home/had/nutch-1.0/filesystem/data</value>
  <description>Determines where on the local filesystem an DFS data node
should store its blocks. If this is a comma-delimited list of directories,
then data will be stored in all named directories, typically on different
devices. Directories that do not exist are ignored.</description>
</property>
<property>
  <name>dfs.replication</name>
  <value>1</value>
  <description>Default block replication. The actual number of replications
can be specified when the file is created. The default is used if
replication is not specified in create time.</description>
</property>
<property>
  <name>mapred.tasktracker.tasks.maximum</name>
  <value>4</value>
  <description>
    The maximum number of tasks that will be run simultaneously by
    a task tracker. This should be adjusted according to the heap size
    per task, the amount of RAM available, and CPU consumption of each task.
  </description>
</property>
<property>
  <name>mapred.map.tasks</name>
  <value>997</value>
  <description>The default number of map tasks per job.  Typically set
to a prime several times greater than number of available hosts.
  Ignored when mapred.job.tracker is "local".
  </description>
</property>
<property>
  <name>mapred.reduce.tasks</name>
  <value>79</value>
  <description>The default number of reduce tasks per job.  Typically set
  to a prime close to the number of available hosts.  Ignored when
  mapred.job.tracker is "local".
  </description>
</property>
<property>
  <name>mapred.child.java.opts</name>
  <value>-Xmx2000m</value>
  <description>
    You can specify other Java options for each map or reduce task here,
    but most likely you will want to adjust the heap size.
  </description>
</property>
<property>
  <name>mapred.system.dir</name>
  <value>/home/had/nutch-1.0/filesystem/mapreduce/system</value>
</property>

<property>
  <name>mapred.local.dir</name>
  <value>/home/had/nutch-1.0/filesystem/mapreduce/local</value>
</property>

</configuration>