If you don't get any help from the Forum, go to one of your local Paint Retailers (found in the Yellow Pages under PAINT - RETAIL) and describe the problem to them. I'm gonna suspect that you'll need to Prime/Seal the wall first, then paint, but let them tell you. I also suggest you bring with you the paint and/or primers you used in case they have any question about what you've done already. This way, there's no question as to what you used.