Hi Wendell,
Thanks for the bug report. I was able to reproduce and fix this problem. Basically it was not resolving the relative url correctly when running in a virtual directory (it worked fine in root sites). This is now fixed in our source code repository if you are working with the source code. If not a workaround you could use, is use CKeditor and then edit the file /ClientScript/ckeditor-mojoconfig.js
change this line:
config.smiley_path = '/Data/SiteImages/emoticons/';
like this to reflect your sub directory
config.smiley_path = /SscIntranet/Data/SiteImages/emoticons/';
Note that this is just a workaround for the current version and your installation, the real fix is different and is done from C# code and is fixed now in our source code repository for all 3 editors.
Best,
Joe