Custom Sidebars Pro is Crashing whenever I try to create a new sidebar or edit a custom sidebar.

Everytime I fire up Custom Sidebars Pro to build a new sidebar, I get a spinning wheel of death upon clicking the Create Sidebar button. If I reload the page later, the sidebar has been created. When I open it to begin to edit I run into the same problem: when I click the button trying to customize the position of the sidebar I get the spinning wheel of death again.

Thanks in advance for your help!