Hello,
I installed OTRS 3.0.11 on Ubuntu 10.04 without any problem. Now I'm trying to configure the customer backend in db2. To do so, I've pasted customised fragment of Kernel/Config/Defaults.pm into Kernel/Config.pm and after this I have the following error:

install_driver(db2) failed: Can't locate DBD/db2.pm in @INC (@INC contains: /usr/sbin/../../Custom /usr/sbin/../../Kernel/cpan-lib /usr/sbin/../.. /usr/Custom /usr/Kernel/cpan-lib /usr /opt/otrs/Custom /opt/otrs/Kernel/cpan-lib /opt/otrs/ /etc/perl /usr/local/lib/perl/5.10.1 /usr/local/share/perl/5.10.1 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.10 /usr/share/perl/5.10 /usr/local/lib/site_perl . /etc/apache2) at (eval 195) line 3.
Perhaps the DBD::db2 perl module hasn't been fully installed,
or perhaps the capitalisation of 'db2' isn't right.
Available drivers: DBM, ExampleP, File, Gofer, Proxy, Sponge, mysql.
 at /opt/otrs//Kernel/System/DB.pm line 210

Customized Kernel/Config.pm configuration fragment is:
    # CustomerUser
    # (customer user database backend and settings)
    $Self->{CustomerUser2} = {
        Name   => 'Database Backend',
        Module => 'Kernel::System::CustomerUser::DB',
        Params => {
            # if you want to use an external database, add the
            # required settings
            DSN => 'DBI:db2:db_name:some.server.com:50000',
            User => 'db2inst1',
            Password => 'top_secret',
            Table => 'otrs_customers',
            # CaseSensitive will control if the SQL statements need LOWER()
            #   function calls to work case insensitively. Setting this to
            #   1 will improve performance dramatically on large databases.
            CaseSensitive => 0,
        },

        # customer uniq id
        CustomerKey => 'login',

        # customer #
        CustomerID             => 'customer_id',
        CustomerValid          => 'valid_id',
        CustomerUserListFields => [ 'first_name', 'last_name', 'email' ],

#        CustomerUserListFields => ['login', 'first_name', 'last_name', 'customer_id', 'email'],
        CustomerUserSearchFields           => [ 'login', 'first_name', 'last_name', 'customer_id' ],
        CustomerUserSearchPrefix           => '*',
        CustomerUserSearchSuffix           => '*',
        CustomerUserSearchListLimit        => 250,
        CustomerUserPostMasterSearchFields => ['email'],
        CustomerUserNameFields     => [ 'title', 'first_name', 'last_name' ],
        CustomerUserEmailUniqCheck => 1,

#        # show now own tickets in customer panel, CompanyTickets
#        CustomerUserExcludePrimaryCustomerID => 0,
#        # generate auto logins
#        AutoLoginCreation => 0,
#        # generate auto login prefix
#        AutoLoginCreationPrefix => 'auto',
#        # admin can change customer preferences
#        AdminSetPreferences => 1,
#        # use customer company support (reference to company, See CustomerCompany settings)
#        CustomerCompanySupport => 1,
#        # cache time to live in sec. - cache any database queries
#        CacheTTL => 0,
#        # just a read only source
        ReadOnly => 1,
        Map => [

            # note: Login, Email and CustomerID needed!
            # var, frontend, storage, shown (1=always,2=lite), required, storage-type, http-link, readonly, http-link-target
            [ 'UserTitle',      'Title',      'title',      1, 0, 'var', '', 0 ],
            [ 'UserFirstname',  'Firstname',  'first_name', 1, 1, 'var', '', 0 ],
            [ 'UserLastname',   'Lastname',   'last_name',  1, 1, 'var', '', 0 ],
            [ 'UserLogin',      'Username',   'login',      1, 1, 'var', '', 0 ],
            [ 'UserPassword',   'Password',   'pw',         0, 0, 'var', '', 0 ],
            [ 'UserEmail',      'Email',      'email',      1, 1, 'var', '', 0 ],

#            [ 'UserEmail',      'Email', 'email',           1, 1, 'var', '$Env{"CGIHandle"}?Action=AgentTicketCompose&ResponseID=1&TicketID=$Data{"TicketID"}&ArticleID=$Data{"ArticleID"}', 0 ],
            [ 'UserCustomerID', 'CustomerID', 'customer_id', 0, 1, 'var', '', 0 ],

#            [ 'UserCustomerIDs', 'CustomerIDs', 'customer_ids', 1, 0, 'var', '', 0 ],
            [ 'UserPhone',        'Phone',       'phone',        1, 0, 'var', '', 0 ],
            [ 'UserFax',          'Fax',         'fax',          1, 0, 'var', '', 0 ],
            [ 'UserMobile',       'Mobile',      'mobile',       1, 0, 'var', '', 0 ],
            [ 'UserStreet',       'Street',      'street',       1, 0, 'var', '', 0 ],
            [ 'UserZip',          'Zip',         'zip',          1, 0, 'var', '', 0 ],
            [ 'UserCity',         'City',        'city',         1, 0, 'var', '', 0 ],
            [ 'UserCountry',      'Country',     'country',      1, 0, 'var', '', 0 ],
            [ 'UserComment',      'Comment',     'comments',     1, 0, 'var', '', 0 ],
            [ 'ValidID',          'Valid',       'valid_id',     0, 1, 'int', '', 0 ],
        ],

        # default selections
        Selections => {

#            UserTitle => {
#                'Mr.' => 'Mr.',
#                'Mrs.' => 'Mrs.',
#            },
        },
    };

I'm new to OTRS and Perl so I'll appreciate any help.

--
Regards,
Grzegorz