I suggest to try Oracle Linux 6.5 64-bit.
Any helpful hints to solve this is appreciated.
The version i tried (6.2,6.3,6.4) all are 32 bit. We have to use 32 bit this time because the EBS team is not yet ready with 64bit. Is there a work around to install OEL UEK 32 bit but this much of memory (64 GB)?