I downloaded hibernate 2.1.7c and ant 1.6.2, installed all as described. I copied the JDBC-Files for firebird (ver 1.5.5) to the lib directory. The commant 'ant eg' ends with the following message:

Buildfile: build.xml
[taskdef] Could not load definitions from resource clovertasks. It could not be found.

eg:
[echo] Remember to place your JDBC driver in the lib directory!
[echo] This target is not runable from a CVS export/checkout!
[java] Exception in thread "main" java.lang.ExceptionInInitializerError
[java] at org.hibernate.auction.Main.main(Main.java:356)
[java] Caused by: org.apache.commons.logging.LogConfigurationException: java.lang.VerifyError: (class: org/apache/log4j/LogManager, method: <clinit> signature: ()V) Incompatible argument to function (Caused by java.lang.VerifyError: (class: org/apache/log4j/LogManager, method: <clinit> signature: ()V) Incompatible argument to function)
[java] at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:538)
[java] at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
[java] at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
[java] at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
[java] at net.sf.hibernate.cfg.Configuration.<clinit>(Configuration.java:94)
[java] ... 1 more'
[java] Caused by: java.lang.VerifyError: (class: org/apache/log4j/LogManager, method: <clinit> signature: ()V) Incompatible argument to function
[java] at org.apache.log4j.Logger.getLogger(Logger.java:85)
[java] at org.apache.commons.logging.impl.Log4JLogger.getLogger(Log4JLogger.java:229)
[java] at org.apache.commons.logging.impl.Log4JLogger.<init>(Log4JLogger.java:65)
[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
[java] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
[java] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
[java] at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
[java] at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
[java] ... 5 more

BUILD FAILED
/opt/hibernate/build.xml:509: Java returned: 1

Does anyone know what's the problem. Thank you for any help - I'm new with hibernate.