# map returns a list so although
print password(5); # result abcdefgh
$p = password(5); print $p ; # result 8

# one fix is to use
return join '',map { $c[ rand @c ], $v[ rand @v ] } 1..4;
[download]

sub password
  {
    my( $s ) = @_;
    srand( $s ^ time );
    my @c = split / */, "bcdfghjklmnpqrstvwxyz";
    my @v = split / */, "aeiou";
    return map { $c[ rand @c ], $v[ rand @v ] } 1..4;
  }
[download]

I don't know what you're talking about, and I suspect you don't either.
The technique I showed worked perfectly for me.
I'd ask that you try it again.
Here's how I instrumented the code to prove myself right. (Note that the rp sub must come before, because of the prototype.)

  sub rp($$$)
  {
    my $array_name = shift;
    my $array_size = shift;
    my $val = shift;
    printf "$array_name: %d out of $array_size\n", $val;
    $val
  }

  sub password
  {
    my( $s ) = @_;
    srand( $s ^ time );
    my @c = split / */, "bcdfghjklmnpqrstvwxyz";
    my @v = split / */, "aeiou";
    return map { $c[ rp("c",@c,rand @c) ], $v[ rp('v',@v,rand @v) ] } 
+1..4;
  }
[download]

jdporter
The 6th Rule of Perl Club is -- There is no Rule #6.