The return value of system should be shifted to the right 8 bits ( $number>>8; ) to get the real return value. That winds up with 255. But, I can't find any info on the return codes for copy anyway.

If there's some error message printed, you might add a "cmd /k " to the beginning, which should spawn a command window that will try the copy and go to a prompt, while your app waits. I don't have a Windows box nearby, so I can't test that. You might also try redirecting the output of the command into a file, but I also don't know if that works. Windows is too quirky for my tastes...