It looks like you aren't publishing to SharePoint.
The XSN is a cab file package. Publishing to a file share is not going to magically uncab and extract the DLL and remove it. Not something that happens. Just like most conspiracy theories. Too complex.
So, my hunch is that your site is not in your domain or your IE settings are such that it doesn't think it's local intranet or some other such manifestation.
May the force be with you,