I'd do what Jeff said - it could also be running out of memory, or just timing out. In that RegistrationData file, on top adding a error_reporting(E_ALL) and ini_set('display_errors', 'on') might yield some errors.
You can disable caching in app.config (it's disabled by default now for the next release)
Also, Mark, if you can give me access to the server and page, I can try to take a look