It was reported on the users@ list: http://tomcat.markmail.org/thread/44rnbj7gbkevzb32 SEVERE: Unable to perform replication request. java.lang.NullPointerException at org.apache.catalina.ha.tcp.ReplicationValve.isRequestWithoutSessionChange(ReplicationValve.java:554) It will occur when ReplicationValve#filter attribute has an empty value.
It is fixed with r1059379 and will be in 7.0.7.