The problem with the unrecognized cpu is most likely a bios bug.
Go get the program called cpu-z, see if that will recognize your processor.
Also on the asus site, it doesn't seem to support the phenom right now...maybe later on they will release a bios update for it.
It you look on the bios version 0902 the description says this:
M2N-E SLI BIOS version 0902
Support new CPUs. Please refer to our website at: ASUSTeK Computer Inc.-Support-
Fixed system will show "AMD Processor Model Unknown" when AM2 6000+ CPU is installed.