The license that you are using is a bundle of products..
Symantec Endpoint Protection 11.0.xxxx
Mail Security for lotus,Exchange and SMTP.
Since you have this license you use the serial number to download the latest version of Symantec Endpoint Protection as it is fully compatible with Windows 2008
https://fileconnect.symantec.com
version is 11.0.4202.xx MR4MP2