Domaing Mapping on a parked Domain

Hello!
I have two domain names registered with my hosting company.
1) Youthstories.org is the primary domain
2) AsianYouthDay.org is a parked domain

On my MU installation under youthstories.org, I created another site "ayd.youthstories.org." I would like to map 'asianyouthday.org' to 'ayd.youthstories.org.'

I've gone through what I believe to be the correct steps.. but when I try to map the domain under the 'ayd.youthstories.org' dashboard, the computer continues to process.. and never finishes mapping the domain.

Any guidance would be much appreciated!!

Best regards,
Calvin