How can a fully encrypted homomorphic program resist copying?
Homomorphic program encryption, assuming you want it fully operational, is not possible. At some point of time actual operations are executed (directly or in obfuscated form).
Encryption of any kind does not prevent copying, because with physical access to hard drive you can make verbatim copy at any moment.
There is also a huge slowdown with program obfuscation (like in Gentry's garbled scheme)/communication that drastically reduces realistic use.