you have correct IP defined for localhost i.e., 127.0.0.1?
R12 Rapidwiz Postinstall Steps Http, Login page, Virtual directory, JSP, Help Page Fails (Doc ID 414414.1)
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Is this for R12.1 or R12.2?
Make sure you have configured all pre-requisites before starting your Installation.
X A H E E R
May be the host entry not configured properly, share your application server host entries.