well either there are no dirs named /media/second/testdisk/linux/recup_dir.1 .. /media/second/testdisk/linux/recup_dir.262, or you don't have rx permission, or there are no files in those dirs ending in .mp3, or you don't have permission to write to /home/zack/music. this is why you should check if system calls succeed.

try

chdir($dir) or die "Can't chdir to $dir: $!";
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and

copy($_,$music) or die "Can't copy $_ to $music: $!";
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