Paul and I went to a century home seminar by Chris Cooper of Edifice Magazine, last fall and were taught a good trick with Borax regarding musty basement smells. First off, open your basement windows to let the air circulate. That's what the windows are for. Now take a 2 kg box of Borax and mix with 2 gallons boiling water. Put in a 2 gallon sprayer and spray the wood and masonry in the basement. Let it dry. Borax has sodium in it and mold and mildew will be killed immediately. Every time your basement gets damp, it will reactivate the borax and kill of any chances of mildew coming back.
Anyone interested in preserving their heritage home or keeping their newer home in good repair should check out one of his seminars.