Java Help

Hey all! I'm trying to run a private RuneScape server/client on Ubuntu Dapper but I keep getting this: tommy@dad:~/Desktop/Moparscape$ java -noverify -Xmx500m -cp ./MoparScape.jar: Bot 0 Exception in thread "main" java.lang.NoClassDefFoundError: java/lang/StringBuilder at Bot.<clinit>(Bot.java:107) Dad suggested I consult the list and I figure someone knows what I'm doing wrong. The site I got the client from is: http://www.moparscape.org/smf/index.php/topic,6915.msg70691.html Gurus bestow thy knowledge!! Tommy