I've encountered this problem sometimes while installing OBIEE on Oracle Linux: during installation process "Creating ASInstace" task was unable to be completed.
This seems to be a well know issue infact it has a pretty good amount of threads and discussions over OTN and luckily it's simply solvable by editing "/etc/hosts" file.
The trick is to insert first the machine IP address and then loopback address.
Edit host file in a similar way according to your network configuration.
[oracle@orcl ~]$ nano /etc/hosts
Start a new OBIEE installation and this time "Creating ASInstace" will be completed successfully.