CiviEvent Registration Invoice Fatal Error

Just updated to version 4.6.2.

When people are registering for an event on our site,
they et a fatal error. (see attachment)
The Event registration is submitted.

• no email is sent
• no invoice is created
  when Automatically send Invoice is checked in the CIVI Contribute Module Settings.
  20
  confirmation occurs and confirmation Email is sent, when I uncheck automatically send invoice in the Civi Contribute Module Settings. However Users do not get any Invoice.

I reverted all customized System Messages to default.

I am also attaching what I found in the log

The registration page is quite complex and can be seen here.
http://www.3dkiss.org/?page_id=487&lang=en