Actually it is because he is publishing it, instead of just sending him the right file:
C:\Users\{UserName}\Documents\Visual Studio 2010\Projects\{ProjectName}\{ProjectName}\bin\Debug
OP just debug once (F5), then navigate to this and send him the .exe - executable file to your friend.
Example: My username for my computer is RDCA, and my project is called Contra
C:\Users\RDCA\Documents\Visual Studio 2010\Projects\Contra\Contra\bin\Debug
C:\Users\{UserName}\Documents\Visual Studio 2010\Projects\{ProjectName}\{ProjectName}\bin\Debug
OP just debug once (F5), then navigate to this and send him the .exe - executable file to your friend.
Example: My username for my computer is RDCA, and my project is called Contra
C:\Users\RDCA\Documents\Visual Studio 2010\Projects\Contra\Contra\bin\Debug