Sounds like it might be the NIC driver errata http://www.intel.com/support/motherboards/server/sb/CS-031086.htm?wapkw=(high+cpu+NIC)
Connect the 2 NICs to each other should let the instlation complete so you can update the drivers and firmware.
Thank you so so much!
This one I shouldn't have figured out myself! Great and helpfull answer!
I tried doing the firmware updates using IDA but this wont work (not correct package?)
but I'm sure I downoaded the right package.because I tried to install that same package using EFI and that worked like a charm!
After the actions in the article mentioned everything worked just fine and I got a brand new clean 2008 R2 server running.
Again: thank you very much!