.NET Framework Problem for x64 OS

Hello ,
my name is Stephan..

Let me explain a bit...

well i am going to run a GameServer named ''MuOnline''
and i need to have the .NET Framework 3.5 for x64 Installed..

when i try to install it i got this...
ScreenShot1



And then i tried the NET Framework 3.0 x64
but i got this error..
ScreenShot2


i did exactly what it needed but Not Helped.


Well i would love ,if someone know's / can help me for this Prob..



-With Much Respect --
---Stephan Kalanidis-
------Regards----



And thanks again !


Have a Nice Day