I didnt think winuae would let you use both net options at the same time but ...oh well. When using winpcap, youll need to use a tcp stack like amitcp/genesis/miami and uaenet.device (make sure enabled in winuae) will be availble to use as the sana2 driver for the tcp stack. This will implant the amiga with bsdsocket.lib so make sure this option is dissabled in winuae.
Then configure just like an actual amiga and i think youll be good to go, and i can see a reason why the doom link wouldnt work. Youll also be able to browse through this link too.