It will take a few weeks for the floor to adjust to the new digs.Give it another week or so and if the problem is still there then start looking at the wall lines to see if the wood might be too tight and when it expands it has no where to go except against the wall and thus bunches up and then creaks.
If still persists after the 2 weeks or so then do an excorsism on the house and see if that help

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I would say that it is just acclimating though and should subside if not get back to us and let us know what it is doing and we will see if we can come up with an answer for you[8D]
Floorman
floorlayers union local 1310