On first boot it gave me "No acceptable DHCPOFFERS received."
When you say "first boot", do you mean booting the install media or booting the installed OS afterwards?
Usually, a complaint about an *acceptable* offer specifically means that your dhclient.config is requiring certain parameters that your ISP's dhcp server isn't providing. In other words, it's getting an offer but won't use it. Additionally, I've had problems before with certain ISPs where they do something such that setting a 'require' parameter of any sort causes dhclient to always complain the offer isn't acceptable. It's possible that your config got messed up after the upgrade or that coincidentally your ISP changed something on their end at the same time. If it's not already, try changing dhclient.conf to be just a simple "request routers, subnet-mask, broadcast-address, domain-name-servers;" and see if that works.
On the other hand, if that error popped up while booted from the install media, I'm not sure what that means. I've seen weird stuff like that when certain bios features mess with the networking, like VLANs or board-level VPN. That board does IPMI shared over one of the two ethernet ports, right? Try messing with the settings for that.
