I see a couple of problems. Frist, it is usually not a good idea to use RPM to install software. RPM does not resolve software dependencies and prevent you from damaging system integrity. The better solution is to use the YUM utility. In your example, the command would be:
# yum install binutils compat-libstdc++-33
The YUM utility can access packages from the instalaltion DVD (file) as well as network (http) or Oracle Public yum service.
See Oracle Public Yum Server for more details. Your error message suggests that you do not have your network configured properly, which is a complete separate issue and requires a lot more informaiton about your enviornment and instalaltion to troubleshoot.
If you can browse the internet from the same OS and access Oracle Public yum then I see no reason why it should fail when using command line. I can only assume there is something about your setup that you have not been explaining, such as OS virtualization.
You also have some syntax or type in your wget command (rpo vs repo). Perhaps try:
su - root
rm -f public-yum-el5.repo
If this does not work, your network or DNS configuration is not working.