Error with

When i try to use exporter-, i am getting the below error :

java.lang.UnsupportedClassVersionError: org/vaadin/haijian/filegenerator/PdfFileBuilderjava.lang.UnsupportedClassVersionError: org/vaadin/haijian/filegenerator/PdfFileBuilder

But in my local machine it just works fine. Which means with JDK7 it is working fine and with JDK6 it is not i guess.

Can you guys help me what can i do to fix this. Do i need to change the version of exporter?