Hi,
the DHCP server module referred to in these posts is extremely old, and I'm fairly sure that it will not work with recent ns-3 releases without a relevant upgrade effort.
To prevent the question: using an extremely old ns-3 release just to be able to run that DHCP server is very hard (compiler compatibility issues) and generally speaking a very bad idea (bugs).
The best advice I can give is to see if you can upgrade the DHCP code, or if the actual address assignment methods supported by ns-3 are enough.
Cheers,
T.