Not sure myself what the flags you used mean entirely, except for "pci=nommconf" which tells the kernel NOT to use MMconfig to identify PCI devices, but instead to use the "Direct" method and/or "BIOS" calls for identifying PCI devices.
Surely a quick Google can supply you with the functions of the other flags.
What happens now if you try booting the system with NONE of these flags?
How about if you remove one or more of them? Like remove the "irqpoll"?
Try changing the "pci=nommconf" to "pci=direct" or "pci=bios" or "pci=nodirect" or "pci=nobios" and see how that goes. (Note that I don't know all of, nor necessarily the right syntax of, all the possible boot parameters you could use. Again, Google is your friend.)
If you could possibly do a diff (compare) the configuration of your OLD kernel, to that of your new installations kernel, you might just come across the exact promlem/solution.
Finally, what will ultimately become important is what type of NIC it is, and whether you have the support for it in the kernel build. Since it worked on the older system, chances are good it will work again, once you get past this issue of it being undetected.
Meanwhile, also please post for us the output of the command "lspci" from a root console. That may get us started.