SEP 12.1 upgrade failed

hello all,

today I failed to upgrade the SEP client from 11.7X to 12.1X, because of "eorror 1303. the installer has insufficient privileges to access this direcotry"

Also I tried to deploy the upgrade package from  SEPM GUI,and it failed.most of my clients have such problem(we use win7)

I'm sure I use the local admin account to log in and to install the package.

One strange thing: I can not create any folder or files only in the SEP 11.7x application folder (C:\Program Files\Symantec\Symantec Endpoint Protection\) ,but I can do this from remote machine via UNC path.

any one met such case ? Pls help ,thanks