Windows dtest: snapshot_test.py failures

ERROR [CommitLogArchiver:1] 2015-07-24 13:26:39,622 CassandraDaemon.java:181 - Exception in thread Thread[CommitLogArchiver:1,5,main]
java.lang.RuntimeException: java.io.IOException: Exception while executing the command: cp c:\temp\dtest-phi4wd\test\node1\commitlogs\CommitLog-5-1437758795056.log c:  emp     mpkzsvkb/CommitLog-5-1437758795056.log, command error Code: 1, command output: cp: accessing `c:\temp\tmpkzsvkb/CommitLog-5-1437758795056.log': Invalid argument

        at com.google.common.base.Throwables.propagate(Throwables.java:160) ~[guava-16.0.jar:na]
        at org.apache.cassandra.utils.WrappedRunnable.run(WrappedRunnable.java:32) ~[main/:na]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_45]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_45]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_45]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_45]
        at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]