Hi!

I have two link fields as user profile(core) fields. I've included both on registration page/form.

When registration form is submitted it returns fatal error(if field have values):
Fatal error: Cannot create references to/from string offsets nor overloaded objects in /includes/common.inc on line 6614

Last in line / stack:
14 0.7343 35418276 drupal_array_set_nested_value( ) ../form.inc:2052

When browsing back to form it also states
Illegal string offset 'url' ...

I've made several test submissions and as soon as one of these fields are filled in it gives this error.

Therefore I ended up replacing these field with URL module which seems to work and to confirm that perhaps this module has some kind of bug.