Ok, think there's a work-around for this. Go to TOOLS in your toolbar up top. Scroll down to INTERNET OPTIONS. When the dialog box displays, click on the ADVANCED tab. Scroll down through the list to the category name SECURITY. Find the checkbox next to Allow active content to run in files on My Computer. Click Apply, then Ok. Close IE, and re-launch it. Your back button should work now.

This may not be the BEST fix, but it will do for now until Justin or Matt, or whoever can tell us a better solution.