I installed OpenID Provider (6.x-1.0-beta1) and OpenID Provider SREG (6.x-1.0-beta2) modules and tried to log in to 2 different sites (serverfault.com and altdotnet.org) but it does not work. The OpenID login page from my Drupal site is displayed, but when I click on "Yes; always" or "Yes; just this once", the page reloads with an error:

warning: Invalid argument supplied for foreach() in (...)/modules/openid_provider_sreg/openid_provider_sreg.module on line 18.

And it always loops.

When I look into my account, in the "OpenID Sites" tab, there is only one entry with an empty site name. There's only the "Autorelease" checkbox and the date when the site was last accessed.