Plugin: visual form builder 2.2.3 Warning — Missing Fieldset

Hi, just installed the new version of visual form builder pro and got this error message:

Warning — Missing Fieldset
Your form may not function or display correctly. Please be sure to add or move a Fieldset to the beginning of your form.

I then tried to create a new form to see if it was a data conversion problem but the new form also gives me the same warning.

Any idea?

Mike