Logging with log4j and using SMTP appender

Hello!

I have some problems with merlin 3.3.0 and log4j logging implementation.I would like to use SMTP appender for ERROR and FATAL log events.
When I start merlin with following log4j configuration:
log4j.rootLogger=ALL, A1

log4j.logger./mrt-vend-server=ERROR,A2

# A1 is set to be a FileAppender.
log4j.appender.A1=org.apache.log4j.FileAppender


# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.file=mrt-vend-server.log
log4j.appender.A1.layout.ConversionPattern=%d{dd MMM yyyy HH:mm} [%t] %-5p %c - %m%n

log4j.appender.A2=org.apache.log4j.net.SMTPAppender
log4j.appender.A2.SMTPHost=server01
[email protected]
[email protected]
log4j.appender.A2.subject=MRT Vend Server logs
log4j.appender.A2.bufferSize=5

I get this exception:

---- error report --------------------------------------------------------------
Exception: java.lang.NoClassDefFoundError
Message: javax/mail/Multipart
---- stack trace ---------------------------------------------------------------
java.lang.NoClassDefFoundError: javax/mail/Multipart
java.lang.Class.forName0(Native Method)
java.lang.Class.forName(Class.java:141)
org.apache.log4j.helpers.Loader.loadClass(Loader.java:160)
org.apache.log4j.helpers.OptionConverter.instantiateByClassName(OptionConverter.java:309)
org.apache.log4j.helpers.OptionConverter.instantiateByKey(OptionConverter.java:112)
org.apache.log4j.PropertyConfigurator.parseAppender(PropertyConfigurator.java:620)
org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:603)
org.apache.log4j.PropertyConfigurator.parseCatsAndRenderers(PropertyConfigurator.java:524)
org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:408)
org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:432)
org.apache.log4j.PropertyConfigurator.configure(PropertyConfigurator.java:327)
org.apache.avalon.logging.log4j.Log4JLoggingFactory.configureURL(Log4JLoggingFactory.java:203)
org.apache.avalon.logging.log4j.Log4JLoggingFactory.configure(Log4JLoggingFactory.java:164)
org.apache.avalon.logging.log4j.Log4JLoggingFactory.create(Log4JLoggingFactory.java:146)
org.apache.avalon.merlin.impl.DefaultFactory.createLoggingManager(DefaultFactory.java:578)
org.apache.avalon.merlin.impl.DefaultFactory.create(DefaultFactory.java:188)
org.apache.avalon.merlin.cli.Main.<init>(Main.java:301)
org.apache.avalon.merlin.cli.Main.main(Main.java:255)
--------------------------------------------------------------------------------

I tried put mail.jar and activation.jar in block.xml and in java classpath, but I still get this exception.

Can anyone help me?

Thanks

Jaroslaw Palka