I'm also trying to get my OTRS windows installation to connect to AD. I wasn't really able to figure out the config setup in OTRS ( it's almost unusably slow on my system... ) so I've been trying to work out how to add LDAP authentication to my config.pm.
    It looks like it's working, (I have no errors in the apache error.log, nor do I get an error accessing customer.pl ) but I can't log in and when I'm logged on as a user I can't pull up any customer list.
 
Here's the config.pm I've been using:
 
#   Authmodule information                                  #
   $self->{'AuthModule'} = 'Kernel::System::Auth::LDAP';
   $self->{'AuthModule::LDAP::Host'} = '192.168.42.245';
   $self->{'AuthModule::LDAP::BaseDN'} = 'dc=bocc, DC=monroecounty-fl, dc=gov';
   $self->{'AuthModule::LDAP::UID'} = 'sAMAccountName';
   $self->{'AuthModule::LDAP::SearchUserDN'} = 'CN=otrs helpdesk, CN=users, dc=bocc, DC=monroecounty-fl, dc=gov';
   $self->{'AuthModule::LDAP::SearchUserPW'} = 'password';
  
#   Customer Authentication                                 #
   $Self->{'Customer::AuthModule'} = 'Kernel::System::CustomerAuth::LDAP';
   $Self->{'Customer::AuthModule::LDAP::Host'} = '192.168.42.245';
   $Self->{'Customer::AuthModule::LDAP::BaseDN'} = 'cn=users, dc=bocc, DC=monroecounty-fl, dc=gov';
   $Self->{'Customer::AuthModule::LDAP::UID'} = 'sAMAccountName';
   $Self->{'Customer::AuthModule::LDAP::SearchUserDN'} = 'CN=otrs helpdesk, cn=users, dc=bocc DC=monroecounty-fl,dc=gov';
   $Self->{'Customer::AuthModule::LDAP::SearchUserPw'} = 'password';
 
 
 

#   Get Customer Information                                #
  $Self->{CustomerUser} = {
   Name =>'LDAP Backend',
    Module => 'Kernel::System::CustomerUser::LDAP',
    Params => {
      Host => '192.168.42.245',
      BaseDN => 'DC=monroecounty-fl,dc=gov',
      SSCOPE => 'sub',
      UserDN => 'CN=otrs helpdesk, cn=users, dc=bocc, DC=monroecounty-fl, dc=gov',
      UserPw => 'password',
    },
    CustomerKey => 'sAMAccountName',
    CustomerID => 'mail',
    CustomerUserListFields => ['sAMAccountName', 'cn', 'mail'],
    CustomerUserSearchFields => ['sAMAccountName', 'cn', 'mail'],
    CustomerUserPostMasterSearchFields => ['mail'],
    CustomerUserNameFields => ['givenname', 'sn'],
    Map => [
      # note: Login, Email and CustomerID needed!
      # var, frontend, storage, shown, required, storage-type
      [ 'UserSalutation', 'Title', 'title', 1, 0, 'var' ],
      [ 'UserFirstname', 'Firstname', 'givenname', 1, 1, 'var' ],
      [ 'UserLastname', 'Lastname', 'sn', 1, 1, 'var' ],
      [ 'UserLogin', 'Login', 'sAMAccountName', 1, 1, 'var' ],
      [ 'UserEmail', 'Email', 'mail', 1, 1, 'var' ],
      [ 'UserCustomerID', 'CustomerID', 'mail', 0, 1, 'var' ],
      [ 'UserPhone', 'Phone', 'telephonenumber', 1, 0, 'var' ],
#       [ 'UserAddress', 'Address', 'postaladdress', 1, 0, 'var' ],
#       [ 'UserComment', 'Comment', 'description', 1, 0, 'var' ],
    ],
  };
 

Any help welcome.
 
Thanks,
 
Eric Udell
Technical Services
Monroe County BOCC
305-289-2504