Hibernate returns error "Class path must be set or restored default"

I am new to Java application based on Hibernate technology. I get some problems in installing my system. I am installed in my friends system. I installed JBOSS Tools (in that only Hibernate tools) in Eclipse Juno (Portable).

I just copied that folder in to my system and I run the Eclipse.exe file and it runs smooth and I am trying to create new Hibernate Configuration file in hibernate perspective.

But I got below error:

Class path must be set or restored default