Slightly damp floor after removing wall

[myxiplx]

I've had a couple of walls removed on the ground floor. The old cement we've uncovered under the walls looks damp in a couple of patches.

I'm planning on using floor leveling compound throughout the ground floor before laying reclaimed oak parquet on top with a bitumen based adhesive. Can I get away with just ploughing ahead, or are the damp patches likely to cause me problems? Should I be thinking of sealing the damp areas first, or is a more drastic solution needed?

I know very little about floors I'm afraid, so any advice on what I should be looking out for would be appreciated.

Ross