Problem: When you start up JNBProxy and attempt to generate a proxy assembly, and Java-side starts up and immediately terminates.
The Java-side process will terminate if there is another process listening on the same port on which the Java-side is listening. One possibility is that a stray Java process may have been left over from another proxy generation session that terminated abnormally. On a Windows platform, open the Task Manager (on Unix platforms, use the ps command) and look for a Java process that cannot be otherwise accounted for. If found, kill that process, and try JNBProxy again.
Another possibility is that a different application is using the post assigned to the Java-side. If you determine this to be the case, change the Java-side's jnbcore.properties file to reflect the new port, and also change the appropriate jnbproxy.config file so that the .NET-side addresses the appropriate Java-side port.