Hard to say without more information.
You might be infected with a clipboard hijacker. A type of malware that replaces the address you copy with one belonging to a fraudster. Try and copy and paste any address in your wallet software, and see if it's the same one.

When we are on the subject of software and wallets, which client did you use to send the coins from and where did you download it from?
Are you absolutely sure your friend sent you the correct address?
is it possible that you did some other work with bitcoin and addresses while copy/pasting that address from your friend, which could have resulted in you accidently copy-pasting a wrong address instead of the one from your friend?