A workstation can`t receive informations from the dhcp server

the error message is the following
proxydhcp service did not reply to request on port 4011

our dhcp server is an microsoft server and there i set the class 60 option
Our PXE / Imaging Server is OES Linux with zenworks 7

On srv/tftp/boot i did configure the settings.txt

Where could be here the problem?

Ramon Lustrati