Apache-Perl cant create directories...sort of

[Juan Antonio Agudo <tag@gmx.de>]

This is on of the strangest thing i've ever seen in dealing with Perl
scripts on apache. I just moved my site to another Server and now I end
up getting errors from movabletype when I want to "Publish" an entry.

The error alway is the same:

"An error occurred:
mkdir /www: Permission denied at 
/var/www/<path.to.site>/html/cgi-bin/lib/MT/FileMgr/Local.pm line 104"

The strange thing is, that if I use the same Method to create a
directory like the author, Benjamin Trott, does - it works just fine.

I used the following script to test this behaviour:

#!/usr/bin/perl -w
use CGI;
use CGI::Carp qw( fatalsToBrowser );
use File::Path;
File::Path::mkpath("/var/www/<path.to.site>/html/xxx", 0, 0777);

All directories below /var/www have are
chown www-data.www-data and cgis have chmod 711.
Has anyone some clues what could have caused this?

btw.: I use debian woody with 2.4 kernel

Y.T.,
Toni