Repeat this to yourself three times, "My Oracle Support is my friend!"
Before embarking on any install project, you should always check the current support notes. For example, I found out from Note 789258.1 that you have to upgrade your version of rapidwiz before you install (x86_64 version).
You can find out what your current rapidwiz version by running ./RapidWizVersion from the startCD/Disk1/rapidwiz directory. I found out my rapidwiz version was 126.96.36.199 and I needed to apply patch 8626041 to get me to 188.8.131.52 (the most current version as of today).
There's also a couple more patches listed in there, so make sure you read and follow the notes.