The client is currently loading. It will take a minute or two: as a benchmark, on a 14,400bps modem it takes about 3 minutes to load across the internet. If you're loading the client directly across a small network, it will be much, much faster.

Since Netscape caches the java class files (if you have it properly configured!), subsequent loads will also be much faster.

If you've already executed and exited Europa, you may wish to reload the client.