I was trying to install Oracle 11g Release 2 (32-bit) on Oracle Enterprise Linux (32-bit) and the hardware was 64 bit.
Everything went fine but at the end of the installation process, the netca and the dbca failed. I started to manually configure them, but they failed again.
After long searching, the answer was that it was a BUG!!!
And the bug number is Bug 8930861, according to metalink note:942076.1
There is no workaround still.
To avoid this, you have to use 64 bit oracle with 64 bit OS on 64 bit hardware