Your ad fails the framebreaker test. When I clicked the link the first time, I got a DNS error. The next couple times I tried it, I got a blank screen. When I copy the target URL to my browser (without the framebreaker test), It loads fine.
I’ve tried it several times, and I’ve observed that the failure occurs only during peak traffic periods. Of course, this is when you WANT your ad to be shown.
NO ACTION NECESSARY
Just be aware that the Viral Mailer bar is doing several redirects and is creating a very large traffic overhead for your ads. The reason it is failing the framebreaker is that the framebreaker timer starts at the first address, and does not consider the subsequent redirects before throwing the timeout error.
If you are not getting the CTR’s for your ads you think you should be getting, I recommend dumping the viral ad bar and go native with the referral URL or simple cloaking.
I’ve had the same problem with the viral link cloaker I use, and have had to dump it to go native with the referral URL.
(sorry for the lengthy explanation – I can’t help it. I’m a network engineer)