ExceptionInInitializerError in Java-to-.NET project

When attempting to use JNBridgePro to call from Java to .NET, I get an ExceptionInInitializerError when making my first call to a proxy. What's wrong?

The most likely reason for this is that your .NET side server hasn't been properly started. Please consult the section on "Starting a .NET side (CLR) for proxy use" in the Users' Guide.

If the .NET side has been started, make sure you have properly configured the Java-side client. See “Starting and configuring a Java-side client” in the Users’ Guide.

If both the .NET side and the Java side have been properly started, please make sure that both the Java side and the .NET side have been properly configured, and that their configuration information agrees with each other (that is, that the communication protocol, host name, and port number are properly set.