Just recently upgraded from CiviCRM 4.5.5 to 4.6.10.
The problem just started happening last month. We changed servers last month, but changing servers does not seem to have been the problem. Everything was functioning until we added paypal as a payment instrument, and then we got a white screen of death for any live version of new membership payment or membership renewal form. The preview version looks like it should.
So I figured now was as good a time as any to upgrade to 4.6.10. The upgrade seems to have worked as designed. All interfaces work, except for the WSOD on any live contribution page still exists.
I would be grateful for ideas on how to fix this.
Edit: I'm getting this php error only for live contribution pages:
PHP Fatal error: Class 'WP_Requirements' not found in /wp-content/plugins/google-calendar-events/google-calendar-events.php on line 46
I found this on Wordpress.org. Perhaps this will help? https://wordpress.org/support/topic/plugin-not-compatible-with-civicrm-profiles