Cloudflare kills dashboard + Relationship tab error. Any ideas?
Disabling Cloudflare or switching off popups as suggested didn't help. Neither did setting up a Cloudflare PageRule to bypass all Civi pages  

But this worked:

I followed the instructions here  (http://wiki.civicrm.org/confluence/display/CRMDOC/Ensuring+Schema+Integrity+on+Upgrades) to clean up my database schema, and then the upgrade to 4.6.4 worked - and fixed the problems.