Exception thrown when I restart one of the nodes

[Ramzi Rabah]

Hi all:
I am using version 0.4.2 of Cassandra, and whenever I restart one of
the nodes only I am getting the following exception consistently:
INFO - Compacting
[/disk1/cassandra/data/Keyspace1/Datastore-1-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-2-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-3-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-4-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-7-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-10-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-13-Data.db,/disk1/cassandra/data/Keyspace1/Datastore-31-Data.db]
INFO - Replaying
/var/lib/cassandra/commitlog/CommitLog-1258227394451.log,
/var/lib/cassandra/commitlog/CommitLog-1258235275214.log
ERROR - Error in ThreadPoolExecutor
java.util.concurrent.ExecutionException: java.lang.AssertionError
        at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
        at java.util.concurrent.FutureTask.get(FutureTask.java:83)
        at 
org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor.afterExecute(DebuggableThreadPoolExecutor.java:86)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:887)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
        at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.AssertionError
        at org.apache.cassandra.io.SSTableWriter.append(SSTableWriter.java:100)
        at 
org.apache.cassandra.db.ColumnFamilyStore.doFileCompaction(ColumnFamilyStore.java:1103)
        at 
org.apache.cassandra.db.ColumnFamilyStore.doCompaction(ColumnFamilyStore.java:686)
        at 
org.apache.cassandra.db.MinorCompactionManager$1.call(MinorCompactionManager.java:166)
        at 
org.apache.cassandra.db.MinorCompactionManager$1.call(MinorCompactionManager.java:163)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at 
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
        ... 2 more
INFO - Flushing Memtable(Datastore)@349572395

Seems like it's happening in the compaction phase. Any idea why that might be?

Thanks
Ray