Hello fellow Monk.
First of all do not create directories using the system command, instead use perl build in mkdir(); function.

I understand that you want to create directories recursiv, in example if provided Test1/Test2 you want the Test1 directory to be created first and then Test2 created inside of Test1, did I get it right?

If so here is a simple script that I wrote as an example for your case, it does the job but probably can be better written.

#!/usr/bin/perl
use warnings;
use strict;

my $foldername = "Test1/Test2";
my @folders = split /\//,$foldername;

for (0 .. $#folders) {
mkdir -p $folders[$_];
chdir $folders[$_];
}
[download]

A simple explanation to the code above: We use split to get a list of folder names ( if you want the user to supply the folder names be sure to check if he used a slash ( / ) or a backslash ( \ ) you will have to modify the regular expression in split for this ).

The for loop iterates over the entire list, as you can see inside every iteration we create a directory using mkdir function of perl, and chdir function ( also build in ) to descend into the newly created directory. The loop stops when it creates the last directory from the list.

I do not know why you tried to use the -p switch on the call to windows mkdir, as far as I remember, windows does not support switches on its command line, so you would just create a directory '-p'. I tested my script on windows xp, and it work the way it is supposed to :) hope I this reply will help you at least a bit, or give a new view on the subject. PS.
I came up with another way to get the job done and here it is:

#!/usr/bin/perl
use warnings;
use strict;

my $foldername = "Test1/Test2";
my @folders = split /\/|\\/, $foldername;

map { mkdir $_; chdir $_; } @folders;
[download]

I think that using map will work faster here, and also i modified the regular expression in split so it handles both directories delimited with / and \, it works fine on my windows xp.