Multi-site Domain Mapping Not Working

v3.scout-site.com build plugin page - http://screencast.com/t/bOUQZug4Y
scout-stie.com build plugin page - http://screencast.com/t/nJ5onTlbo

I read that using domain mapping with 2 multi-site builds on one IP was not doable. But my server tech told me they could set up an .htaccess rule to make it work.

They setup the rule and lighthousepointyoga.com now points to v3.scout-site.com but when I try to map it I get the following

result when I try to map domain in v3.scout-site.com - http://screencast.com/t/MIgBQCXs0D

Not sure what the issue is or if I am beating a dead horse trying to get this to work.