How old is the flooring? Being that small of cracks, just try, no guarantees, but soak a bath towel in hot water and lay it on the crack areas and see if the wood will absorb some water vapor and expand. It just might assist you. I have seen this used on some home improvement shows. Have not tried it though.
Your other recourse is to tear off the wall moldings and start prying it over if possible.
I would not recommend any fillers, putty, or such.