That version of iRite uses a deprecated version of the CKEditor. It was deprecated before IE 10 was released.
It also used a different file manager to current CKEditor versions, so updating the files manually will be problematic.
actually, since you are still on classic ASP, I'm not sure that updating the files manually will work at all, even without the file manager.
I would urge your users to use a different browser, or to use the Developer tool in IE to use the IE 8 rendering engine.