Explanation:

Here we're telling the Script node where to find the Java .class file. Remember, in Java, you write your source code with an extension of .java -- then you compile it into a file with an extension of .class. THIS is the filename to pass to the Script node. Never use the .java filename in place of the .class filename in this field.

This can also be an absolute pathname (i.e. http://www.foo.com/flash.class)