Not sure on the error you're getting but to run mojoPortal in an intranet without internet access you need to tell it to use locally hosted files for jquery and the AjaxControlToolkit. For the AjaxControlToolkit, add the following to your user.config.
<add key="BundlesUseCdn" value="false" />
For jquery, follow these instructions.
If your skin is calling jquery directly (not using mojoPortal to call it), change the links to the jquery files to locally hosted files.
Hope this helps,