Absolutely it's valid.  I did it on two different computers same result.  Don't get me wrong it works fine.  I get the balance on the key and I can send and receive no problem.

The issue is that:

1.) THe response in the console that I assume should probably say "Success" or something is blank.

2.) The public address appears in the address book instead of my receiving addresses until a restart of bitcoin.  Then it moves over where it belongs and everything works as normal.