Janine, I had a
similar issue and was able to resolve it with the help of Asher's recommendations. The error you are seeing is a generic one, it means Tomcat had some error loading, but without the proper log4j definitions the full stack trace is "eaten" so you are left to guess as to what went wrong. If you follow Asher's steps, in particular about creating the log4j.properties file into <debug runtime>/CATALINA_HOME/common/classes, then it will turn on the logging you need to see what your error is exactly. The one above will write to a log file. I extended mine so that it will write to console output, so you should see the stack trace right in your debugger console output instead of digging through logs. Here's what I used:
# Tomcat context startup logging properties
log4j.rootLogger=info, R, stdout
# Direct log messages to log file
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=./logs/listener.log
log4j.appender.R.MaxFileSize=10MB
log4j.appender.R.MaxBackupIndex=10
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=[%5p] %d %m%n
log4j.logger.org.apache.catalina=info, R
# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
In my case, it turned out there was a port conflict with a TCP port that the debugger used and a TCP port that the SolarWinds TFTP server uses internally - port 8099. If you happen to be running SolarWinds, try stopping all it's services and see if that helps. To fix it, you can change the SolarWinds port in question like so:
http://knowledgebase.solarwinds.com/kb/questions/2016/Changing+the+internal+communication+port+used+by+TFTP+Server