May be something to do with file permissions.. Try logging to console first, and then to some files.. in windows try '\\' instead of '\'.eg

c:\\test.log)
log4j.rootLogger=INFO, logFile
log4j.appender.logFile=org.apache.log4j.DailyRollingFileAppender
log4j.appender.logFile.file=c:\\test.log
log4j.appender.logFile.append=true
I have had problems too with log4j1.2 when used in a web application in WLS6.1 for Solaris. Even though log4j1.2.6.jar was in WEB-INF\lib directory of the war, while deploying, WLS6.1 gave an error:
java.lang.NoClassDefFoundError: org/apache/log4j/Category.
Same war when deployed to WLS6.1 on an XP machine did not give any problems. WLS6.1 on solaris gave this problem.
This link partially solved my problem
Still need to figure out why WLS6.1 for solaris doesn't take log4j1.2 in WEB-INF\lib to its classpath... Any Ideas...