Check the registry settings...there may be something obvious like the listen address or something. I don't have a PXE Rep, but I spent time in the registry keys back in the day and I thought I remembered such a setting.
Try here. Should let you delete the second IP address it is trying to find as was the case on ours.
I can't find HKEY_LOCAL_MACHINE\SOFTWARE\Intel\PXE\ProxyDHCP\Discovery_List
there's no \Intel\PXE\ProxyDHCP\Discovery_List on it, Do i missed something on installation state?
For 64 bit Systems the key is under HKLM\SOFTWARE\Wow6432Node\Intel\PXE\ProxyDHCP\Discovery_List, but the configuration will be reloaded when you re-start LANDesk(R) PXE Service (LANDesk 9 SP2)