Membership plugin registration error

Hello,

Just to state - default theme (2012) and no other plugins except Membership.

After successful registration, the form redirected from /register-2/ (the form page) to /register-2/false which returned "404".

After that, I received an e-mail from Authorize.net, saying the payment has been made (Sandbox account) and checked the back-end. The subscription was active.

After I removed the subscription from that test account, and tried again, I get this error:

Fatal error: Cannot use string offset as an array in /home/***/domains/***.net/public_html/***/wp-content/plugins/membership/classes/Membership/Render/Gateway/Authorize/Form.php on line 116

Just above that error, there is a radio button: <input type="radio" name="profile" value="2">

Please advise,
Alex