Ctools modal_form not working with webforms
The issue is your modal link path isn't correct. When using Webforms the link needs to use the Node ID (nid), not the form clean-url (/modal_forms/nojs/webform/[nid]) Here's how the link would look considering your example above:

&lt;a class="ctools-use-modal ctools-modal-modal-popup-large" href="/modal_forms/nojs/webform/123123"&gt;Free Trial&lt;/a&gt;