Please go to the Joomla -> Global Configuration area and set Error Reporting to "Maximum". The white page should then show the PHP error that's causing problems, which will help us diagnose things.
If that doesn't help, trying disabling any Social Profile or Open Graph plugins you have enabled and test again. If that works, re-enable the plugins one by one to narrow down the culprit and we'll gladly help however we can.
Thanks,
Alex