Hello,
On what machines are you trying to deploy the SEP packages?
There are different ways to deploy the package, check this Article:
About client deployment methods
http://www.symantec.com/docs/HOWTO81302
Secondly to Answer your question, check these Articles:
Steps to prepare computers to install Symantec Endpoint Protection 12.1 client
http://www.symantec.com/docs/TECH163112
How to prepare computers for remote deployment
http://www.symantec.com/docs/HOWTO16365
Preparing Windows operating systems for remote deployment
http://www.symantec.com/docs/HOWTO81300
Installing Symantec Endpoint Protection clients remotely
http://www.symantec.com/docs/HOWTO59432
Remote Installation Troubleshooting
ftp://ftp.symantec.com/public/english_us_canada/products/symantec_endpoint_protection/11.0/manuals/mr4/remote_troubleshoot.html
Hope that helps!!