Undefined index: #name on webforms after update to 1.30

After updating Clientside Validation module from version 1.27 to 1.30 I'm getting the following error on every webform

Undefined index: #name in clientside_validation_webform_after_build_recurse() (line 73 of C:\wamp\www\mysite\sites\all\modules\clientside_validation\clientside_validation_webform\clientside_validation_webform.module)

On webforms I have 2 textfields for name and subject, 1 email field and 1 textarea field wrapped with fieldset. When I'm logged in there are 3 error messages, for anonymous users there is only one message.

So far I can't find any fix.