In 6.1.0, using a log4j RollingFileAppender (we actually subclass it, but I'm sure it's an issue with at least all FileAppenders), I get this error when it tries to switch from the bootstrap logger to the jboss-logging.xml loggers:
org.jboss.logging.service : Removing bootstrap log handlers
[STDERR] log4j:ERROR No output stream or file set for the appender named [null].
I have a forum thread going here for this. http://community.jboss.org/thread/171093. My jboss-logging.xml file is attached in the forum thread.
Reapplying the 6.0 Final patch from here, fixes the problem: https://issues.jboss.org/browse/JBAS-8791