The reason you have to have a ticket to the show is because it's going to run through when doors open so you'll have to have a ticket to be in the venue. That's all.
As far as why it's on this date and not another... it's not as easy as just picking a date and saying we'll do it there. We have to coordinate with LOTS of people (band, crew, venue, staff) and it has to work for everyone.
Pez, PM me your email address and I'll look into your account issue.