New install or upgrade breaks Image Assist Integration

Hello -

I have done a new install of Drupal 6.6 and also an update. After performing a fresh install, then installing (including pre-requisites) wysiwyg, I installed the Image Assist module. Using the actual icon (for Image Assist) that appears on the node/edit page, I can upload and configure the image, but never insert (always ends with start over). When using the Image Assist button that appears on the rich text edit, a pop-up appears with a blank window.

Performing an upgrade produces the same results (blank window) on a site that was working well with both modules.