Thank you for the snapshot attachment. From the looks of things, Thickbox is unable to display "iframes" in your configuration. Possibly due to code alteration by a gallery plugin or theme template.
To solve this problem, I need to verify your Thickbox setting. Can you send me a snapshot of the view source from WassUp Details main screen? I only need the document head section. You can email me the image or link directly at techfromhel (at) gmail (dot) com, if you don't want others to see this sensitive information.
In the meantime, here is a temporary workaround to display "top stats" in a new window instead of Thickbox: