Use double backslashes within backtiks.

 my $cmd=`mkdir C:\\Windows\\Temp\\myfolder`;
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see perlop#Quote-and-Quote-like-Operators about interpolating

You might want to look at File::Spec, File::Path, and File::Copy. File::Spec is great for performing portable directory and filename operations (you don't have to remember which way the slashes should go). File::Path makes it very easy to create directory trees without having to specifically create all of the intermediate directories. File::Copy is used to copy or move files. As with any function call, you should verify it worked by either performing an independent test or by checking the return value.

use strict;
use warnings;
use File::Path;
use File::Copy;
use File::Spec;

# Assemble a new dir name and create it

my $dirpath = File::Spec->catdir( 'C:', 'dir1', 'dir2' );
mkpath( $dirpath );

# make sure the dir we tried to create exists, using -d (one option)

my $install_error = 0;

unless( -d $dirpath )
{
    $install_error = 1;
}

# (stuff if mkpath failed)

my $pathfile = File::Spec->catfile( $dirpath, 'myfile.txt' );

my $copy_status = copy( 'myfile.txt', $pathfile );

if( $copy_status == 1 )
{
    print "  copied myfile.txt to $dirpath\n";
}
else
{
    print " *** Error copying file: $!\n";
}
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Can you create this directory yourself from the command line ?

On the first two is your code running in the directory where you have permission to make a dir ?

Try running the third but with escaped forwards slashes, ie:

`mkdir C:\\Windows\\Temp\\myfolder`;
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Dear ikegami, ccn and Random_Walk,
Thank you very much for helping me. I tried these three things and they all worked:

`mkdir C:\\Windows\\Temp\\myfolder`;

my $folder="C:\\Windows\\Temp\\myfolder";
my $cmd=`mkdir $folder`;

my $folder="C:\\Windows\\Temp\\myfolder2";
mkdir "$folder", 0755 or warn "Cannot make directory: $!\n";

I really appreciate your help! I guess I got myself confused by the slashes!
Best regards,
shn4002

my $dirname = 'c:/path/to/newdir';
system( 'md', $dirname );
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Thanks Kyoichi! I'll try that as well!