I have the same problem. I installed using "ant install.demo" the jBPM 5.2 and i started the services using "ant start.demo":
:~/jbpm-installer-5.2$ ant start.demo
Buildfile: build.xml
download.h2.check:
[echo] Checking h2 download ...
download.h2:
start.h2:
start.jboss:
check.jboss.version:
start.jboss5:
check.jboss.version:
start.jboss7:
start.eclipse:
start.human.task:
[java] Task service registered usergroup callback ...
[java] Task service started correctly!
[java] Task service running ...
...
but when i try to access the "Process View" in jbpm-console the console crashes. I'm using openjdk6.