Upgrade to WP 3.1.1 causing image problem

After upgrading to version 3.1.1 yesterday, now I can not add an image to a post or page. The icon is there in the visual editor, and on mouseover the cursor turns to a pointing hand for an active link to add an image, but when you click on the image upload button nothing happens.
I want to add a gallery or slideshow to a post, but WP does not seem to recognize shortcode for my image gallery, nor will it allow me to insert images into a post or page since upgrading.
The website I’m working with is https://www.artsatthelake.com

Thanks for any help.