SEP MR4 is not supported on Microsoft Windows Server 2008 R2.
You will need to upgrade to RU5 for R2 support.

http://service1.symantec.com/support/ent-security....

Thomas

If your server is Win 2008 R2, then you should install SEP 11.0 MR5

SEP 11 MR4 or SEP 11 MR4 MP2 is not compatible with Win 2008 R2.

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2009082112345348

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2009070714390948

Thanks Guys!
So is MR4 just not supported, or is it completely imconpatable?

Thanks again!

Not supported but will work, see the comments on this thread regarding R2 installations on MR4 -

"Endpoint Protection 11.0.4/Windows Server 2008 R2 Core Compatability"

https://www-secure.symantec.com/connect/forums/end...

Which are the components installed in the server? 
PTP will show off if you install it because truscan will not work with it.
But application and device control policy will work
If you are planing to install NTP first you have to do a through test in test environment since the firewall can block any type of traffic and ensure that all traffic which is req. to you is allowed.There are some default rules present for fire wall fore more info click here
What  will be role of it?
Depending of the role of the Server you may have to exclude some directories and files from scanning (For some roles it will do the exclusions automatically)