Installation Problem for Sneak Preview WAS 6.40

When I first installed WAS 6.40 ,some errors occurs. And when installation completed, the SAP management console don't work, I can run instance. But components of Netweaver Developer Studio is fine, and it can work, so I decided to uninstall WAS 6.40 except Netweaver developer studio, uninstall is ok. But when I second install WAS 6.40 , system automatically run installtion and complete very fast. The SAP management concole still doesn't work. I am wondering why, can anyone tell me why?