Since you're using RedHat I'm assuming you have a valid license (although version 4 is rather old isn't it?). So connect to RHN, use your license and put your money to work.
If you don't have one, get one and put your money to work.
On the other hand, if you don't want to pay for a license, get CentOS instead, that one's free, RedHat is NOT. Or as a final solution, you can download the packages yourself (Google can help you find them), install manually along with all the dependencies necessary.