There is a KB Article about that for ConfigMgr 2007. It's mainly about the IP Helper (BOOTP) configuration, so it should apply here: http://support.microsoft.com/kb/2024414
Basically it says, check your IP Helper configuration.
Have you seen this threads already?
Contrarily to Configuration Manager 2007, there is no need to install WDS before to enable PXE in Configuration Manager 2012. The distribution point installs it automatically when enabling PXE and this is the recommendation. Otherwise, WDS service will hung as in the following print screen and you’ll not able to to deploy OS.
That error can be related to a wrong boot file name or to IPHelper settings. The option 67 should include SMSBoot\x86\wdsnbp.com otherwise if you use an non Microsoft dhcp like Linux so that will be \\SMSBoot\\x86\\wdsnbp.com
Here is also a great guide for troubleshooting PXE issues: http://blogs.technet.com/b/system_center_configuration_manager_operating_system_deployment_support_blog/archive/2011/10/14/troubleshooting-the-pxe-service-point-and-wds-in-configuration-manager-2007.aspx