use File::Spec;
use File::Copy;

my $file=File::Spec->catfile('\\serverA','dir','subdir','file');
my $newfile=File::Spec->catfile('\\serverB','dir','subdir','file');
my $errorfile=File::Spec->catfile('\\serverA','error_dir','file');

copy $file, $newfile or warn "Unable to copy $file to $newfile. $!";
if ($? > 0) {
 copy $file, $errorfile;
} elsif ($? == 0) {
 unlink $file;
}