Often when we remove the /opt/IBM folder manually to remove a Websphere installation (for reinstalling) this error pops up during the second attempt
Specify a different directory or perform a manual uninstall to remove all packages before reinstalling to the same directory
This happens because the WAS installation is stored in more locations than just the /opt folder. To clean up the system after you accidentally remove the /opt folder,(kill all java processes first)
1) rpm -qa |grep WS
and remove the rpms
2)remove the ~/.WASRegistry file.
3) remove vpd.properties.