RIS not working after upgrade to Windows 2003

Hello,

I have a Windows 2003 server which is an upgrade from a Windows 2000 server.
This server is the primary server in the organization, and is the only
server with domain roles. This server runs the DHCP server, as well as RIS.
After upgrading the server, the RIS server is not working. The DHCP server
is authorized, and I've run risetup -check. In ADSIEdit, the information for
the DHCP servers (in NetServices) appears to be correct, as does the
information in the RIS container.

When the client start, I see the F12 message (network service boot). After
pressing F12, I get a header (Intel PXE-2.0, copyright, etc). The DHCP
message with the MAC address appears, and then the spinning line and ...
sequence. After about 90 second, it stops with the error PXE-E53: No Boot
Filename Received.

The system is assigned an IP address correctly, check in the DHCP lease
table. RIS is set up to respond to unknown clients, and the server has been
verified. I've reset the security on the RemoteInstall folder to make sure
SYSTEM and administrators have the correct permissions. I've removed all the
images from RIS, and installed a clean image using the wizard.

Has anyone else had this problem? Does anyone have any suggestions on how to
get RIS working?

Thanks,
Erick