I had to install Oracle on a RHEL 5 and after some troubles all works good.  Be sure to review all links and verify all paths on your specific system before creating the links.

The following are the steps that I used.

1. Add oracle user and some other stuff

   # groupadd dba
   # useradd -g dba oracle
   # cd /opt
   # mkdir oracle
   # chown oracle:dba oracle
   # cd /opt
   # ln -s path/to/jre1.6.0_11
   (Edit the Disk1/install/linux/oraparam.ini and modify JRE_LOCATION
   variable and set path to our JRE installation from Step 2.
   JRE_LOCATION=/opt/jre1.6.0_11)

2. Kernel settings – Edit the /etc/sysctl.conf and add following lines (I decided to leave default values and did not modify any of these.  These have to be verified)

   kernel.sem = 250 32000 100 128
   kernel.shmmax = 2147483648
   kernel.shmmni = 128
   kernel.shmall = 2097152
   kernel.msgmnb = 65536
   kernel.msgmni = 2878
   fs.file-max = 65536
   net.ipv4.ip_local_port_range = 1024 65000

Note: You need execute “sysctl -p” or reboot system to apply above settings.

1. create access list for oracle to use xwindows

   # xhost +local: oracle (with no space inbetween oracle)

2. Check for required packages:

   rpm -q compat-db compat-gcc-34 compat-gcc-34-c++ compat-libgcc-296 compat-libstdc++-296 compat-libstdc++-33 gcc gcc-c++ glibc glibc-common glibc-devel glibc-headers libgcc make libXp

3. Set environment – add these to /home/oracle/.bash_profile

   ORACLE_BASE=/opt/oracle
   ORACLE_HOME=$ORACLE_BASE/920
   ORACLE_SID=ORCL
   LD_LIBRARY_PATH=$ORACLE_HOME/lib
   PATH=$PATH:$ORACLE_HOME/binexport ORACLE_BASE ORACLE_HOME ORACLE_SID LD_LIBRARY_PATH

4. First Workaround

   su -
   cd /usr/lib
   ln -s libstdc++-3-libc6.2-2-2.10.0.so libstdc++-libc6.1-1.so.2

5. Download and Install:

   rpm -ivh http://oss.oracle.com/projects/compat-oracle/dist/files/RedHat/compat-libcwait-2.1-1.i386.rpm
   rpm -ivh http://oss.oracle.com/projects/compat-oracle/dist/files/RedHat/compat-oracle-rhel4-1.0-5.i386.rpm -nodeps

6. Second Workaround

   su -
   cd /usr/bin
   ln -s gcc34 gcc32

7. Third Workaround

   su -
   cd /usr/lib
   ln -s libgdbm.so.2.0.0 libdb.so.2

8. Run installer

   ./runInstaller

9. When NETCA/DBCA will fail
10. Fourth Workaround

    I suggest to apply 9.2.0.8 patchset before.
    cd $ORACLE_HOME
    rm JRE
    ln -s $ORACLE_BASE/jre/1.3.1 JRE
    cd JRE/bin
    ln -s java jre
    cd i386/native_threads/
    ln -s java jre