The "security and nonsecure items" message in IE is being caused by an issue in Dojo. For more, see the discussion on the WebWork forum.
There is a workaround available from the Dojo mailng list.
In short, line 79 in dojo/src/storage/browser.js
storeParts.push('codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0"');
should be replaced with
storeParts.push('codebase="https://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0"');
Also try to search dojo.js and see if the following exists
_607.push("\tcodebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0\"");
if it does should be replaced with
_607.push("\tcodebase=\"https://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0\"");