oops, sorry, I misunterstood you.
I guess what you are downloading is the whole distribution, isn't it?
I also guess you are downloading the source (.src.) packages, but to install a complete system from src packages is a real nightmare of course not recomended for novices.
What you'll need are the iso images to create the installation CD's.
By the way. In what kind of machine are you installing RHAS 2.1 ?
If it is less or equal than 2 GB RAM and/or less or equal than 2 processors, and/or you are not installing Oracle9 on it, you really shouldn't bother and use a standard distrib.