I suspect that error is actually Generic Trust Failure. Before installing something that claims to be the NET Framework it checks the certificate signing, and if the certificate chain isn't in the current certificate list on the target system you'll get this error.
This article pretty much sums it up, none of the options look good without internet access, except to manually update the root certificates on the target systems:
http://support.microsoft.com/kb/2694321
and there's a section that seems to allow offline approval.