You could try something like this

my $result=`sudo /bin/mount /dev/fd0 /mnt/floppy`;
if ($?) {  # there was an non zero return code
    print "There was an error: $?\n";
    print $result
} else {
    # looks like it worked
}
[download]

With system you get the exit code of the forked child returned, perldoc suggests the following to handle errors.

if ($? == -1) {
    print "failed to execute: $!\n";
    }
    elsif ($? & 127) {
    printf "child died with signal %d, %s coredump\n",
        ($? & 127),  ($? & 128) ? 'with' : 'without';
    }
    else {
    printf "child exited with value %d\n", $? >> 8;
    }
[download]

Cheers,
Random.