Having the pxe rep installed on your dhcp is not supported. Please see http://community.landesk.com/support/docs/DOC-8678.
The reason is that both the dhcp and the pxe are trying to handle requests and they can grab the request before the other process, causing it to fail.
Are you able to boot into PXE or is it failing when you try to boot? What is the error code? Does it happen if you install the pxe rep on a machine that is not the dhcp (you may want to uninstall or stop it on the other servers)? If you are able to boot pxe and it is in WinPE that you are not getting an IP address, then check your drivers in the boot.wim. You may also want to try doing ipconfig /renew to see if it is just a driver delay in getting the card initialized.