The easy way
Note: This will only work if the JDBC jar and zip files are in the Java Runtime "ext" directory -- "java -jar" doesn't look at CLASSPATH.
Put vienna.jar somewhere convenient. Once you have installed the JDBC driver files, you can double-click vienna.jar (on Windows) or "java -jar vienna.jar" on other systems.
Put the JDBC JAR/ZIP files in your Java library extension folder. This way you won't need to frig around with CLASSPATH. If you don't know about the "ext" directory, read your Java documentation under the "Tools" section. The exact location of this directory varies: On my Windows NT 4.0 system it is C:\Program Files\JavaSoft\JRE\1.3\lib\ext.
The hard way
If you need the runtime to use CLASSPATH, do this instead. (In all cases this should be entered as a single line):
On a proper computer
java -classpath $CLASSPATH:/some/directory/vienna.jar \ uk.co.whisperingwind.vienna.MainController
On Microsoft Windows
java -classpath "%CLASSPATH%;\some\directory\vienna.jar" \ uk.co.whisperingwind.vienna.MainController
(Note the ; rather than : and horrid "back slashes").
On Macintosh
I haven't the faintest idea. If anyone knows, please pass it on and I will add it here. But Mac may not have JDK 1.2, so you can't run it anyway. See the links page for Mac hints.