Membership: "cannot modify header" error when Membership upgraded to 3.0

Hello

I'm using Membership Premium 3, Buddypress 1.5.4 and WordPress 3.3.1

I just upgraded from Membership Premium 2.1.4 to Membership 3. There is an error in user registration.

Screen 1: Select a Subscription. User picks subscription level. ok. click "sign up"
Screen 2: Create an Account. User fills out required profile information. ok. click "sign up ->"
Screen 3: navigation and content frame loads, in page body error appears:

Warning: Cannot modify header information - headers already sent by (output started at /home/[mysite]/wp-content/themes/genesis/lib/structure/header.php:31) in /home/[mysite]/wp-includes/pluggable.php on line 669

Warning: Cannot modify header information - headers already sent by (output started at /home/[mysite]/wp-content/themes/genesis/lib/structure/header.php:31) in /home/[mysite]/wp-includes/pluggable.php on line 670

Warning: Cannot modify header information - headers already sent by (output started at /home/[mysite]/wp-content/themes/genesis/lib/structure/header.php:31) in /home/[mysite]/wp-includes/pluggable.php on line 671

Warning: Cannot modify header information - headers already sent by (output started at /home/[mysite]/wp-content/themes/genesis/lib/structure/header.php:31) in /home/[mysite]/wp-includes/pluggable.php on line 866

(looks like some cookie setting in the code? can't quite tell)

The user is actually getting added with the correct subscription in the admin panel, although it doesn't look like it from the front end.

Does this look like an incompatibility with the theme? I'm using GenesisConnect 1.1. If this is a problem with the theme, I'll have to roll back the Membership upgrade, as I can't change the theme and there's no recent upgrade available.

Please let me know what you think,

thanks,

Clare