The first scenario is a duplication of the ignition key with another operating key available.  The second is a duplication without any ignition key available.  I will assume you have a working ignition key available.  There are 2 codes the ignition key has to make it usable to start the car.  There's the mechanical code and the electrical code.  The mechanical code is the physical "cutting" of the key like any other key.  Based on what you said, the mechanical code is correct otherwise the ignition lock would not unlock. What the problem appears to be is the electrical code is incorrect or maybe missing.  Did the local ACE Hardware store determine which electrical code your operating key had with a reading device?  Do you know what the code is?  If so, obviously don't state it here but go back to ACE, explain the problem and have them check to see if the replacement key has the same electrical code as the original.  If not, they cut the wrong key.  If they did not read it or don't know what your referring to then either the replacement key has the wrong electrical code or maybe it's missing.

If you can't resolve the problem with ACE then you will have to go to the dealer.

Also, try the original key again without trying the replacement.  It should work.  The manual mentions in the "second" scenario duplication process that the Ignition Switch must be off for at least 4 minutes before making another attempt at starting the car.

I hope this helps.