I have not used SAS, but in simplistic Java terms every application is organized into class files. When one class calls another, the java virtual machine tries to find that class based upon all the classes that are listed in what is called the classpath. The error you see means that the class TrellisPlot cannot be found in the application classpath. I'd suspect SAS was not correctly installed, is missing a required library (.jar) somewhere in the application structure, or had the classpath configured incorrectly. I'd recommend contacting SAS customer support
All of a sudden one day I got a JRE (Sp?) message fairly similar to yours. I ended calling tech support and I think they had me install a different version of Java. I had origninally looked up my error and tried to do it myself to no avail. But luckily the a guy with a North Carolina accent walked my through the reinstall of Java. Right now some programer is reading this message and thinking, "hlsmith is has no idea what they are writing about and is hopeless". True story.