http/ftp install fail but nfs works

[leilei175 at gmail.com]

Hi, guys
I am trying to install RedHat EL4 remotely.
The way I tried is
insert the disc_1 to boot the raw box -> using dhcp to start network
-> install method selection

When I select http or ftp method and input the http/ftp website name
and directory, it will pop up a dialog box asking me to test the CD
media or skip.
when I choose skip it would went back to the http setup stage(asking
for website name and directory).
This comes to an dead loop.

The network connection should be fine. I exported the installlation
directory on the same server ,and nfs install went well.

Is there anything I'm doing wrong to use http/ftp install method?

Thanks
Lei