I’m having a similar problem with invalid email errors.
We use your ticketing plug-in for our children’s theater tickets and are having issues with two things regarding invalid emails.
1. In general anyone with a .net address gets an invalid email error message and can’t purchase tickets.
2. Someone who has successfully purchased tickets in the past is now unable to purchase tickets using the same attendee information (name, email, etc).
This plugin has really streamlined our ticketing process and I love it!
http://www.trypskids.com/
