Thats not an error. Thats just another log message. The Log4j service in JBoss has a timer task which is scheduled every 60 seconds i guess, which looks for changes to the log4j.xml file. If there are any changes to that file, log4j is reconfigured to reflect those changes. You can safely ignore that message.
you could look at the modified date of the log4j.xml and on the server date. I had this problem when the server date was behind the date of the computer where I changed the log4j.xml. Then jboss compares the system date with the last modified date and realizes a modification on the file. I helped for me to change the log4j.xml on the machine where the jboss is running or fixing any datetime differences.