Getting a 403

I tried two different ways to understand it best for my users. Added http://www.lentbook.com as a parked domain on my http://www.youthsites.com account. That worked fine.

Then I tried a sample site (www.sampleyouthgroupsite.com) had my hosting company not assign it to my account (like a user not having a hosting account). It does not work.

In reading the post, it mentions that I must have a dedicated IP. Is this why it is not working?

Thanks for the help!