Network installation of FC6 hangs

[Marcelo Magno T. Sales]

Hi,

In a lab set up for a Linux course using FC6, I've configured local yum 
repositories for core, extras, updates and livna. The students intall FC6 in 
their machines (16 machines) using these local repositories. However, several 
installations hang while copying files from the server. I can switch to the 
consoles and no error messages are shown, but anaconda stops responding.
Some machines have to restart installation several times until they can get to 
the end of the process. This behavior is apparently random, it can happen 
with any of the lab machines. Also, it can happen while all the 16 machines 
are running the network installation simultaneously or if just one of them is 
running it. The server do not stop responding, because some machines finish 
installation while others hang and I can see httpd answering GET requests by 
watching the apache access log. The hardware is the same in all workstations 
(IBM ThinkCentre, P-IV, 256 MB RAM).
Any idea on how to solve this?

Thanks,

Marcelo