I'm sorry to hear that but I think the issue is that you do not understand the instructions.
ERPXE has an 'erpxe-httpd.conf' file that should be placed under /etc/apache2/conf.d/
In Ubuntu 14.04 /etc/apache2/conf.d was replace with /etc/apache2/conf-available so you need to place the file there and restart the Apache server.
The exact command is:
cp /tftpboot/bin/setup/erpxe-httpd.conf /etc/apache2/conf-available/
That's it.. definitely not rocket science.
Still I do not think this is your issue since Apache only affects HTTP plugins and there are not many of those.
If you are trying to PXE boot and you don't get the ERPXE menu screen then the issue is somewhere else.
Maybe your DHCP config or you TFTP config...
If you can post a screenshot/quote of your error maybe I can be of further assistance.