[exim] Cannot open exim_dbmbuild database in perl

Hi,
I created a database with

# exim_dbmbuild domains domains.db"
# 2 entries written

Problem: I cannot access this database with the following perl script:

#!/usr/bin/perl -w
#
use BerkeleyDB;
print "BDB version: $BerkeleyDB::db_version \n";
my $database = 'domains.db';

tie my %hash, 'BerkeleyDB::Hash',
        -Filename => $database,
        -Flags    => DB_RDONLY
    or die "Cannot open $database: $!     BDB: $BerkeleyDB::Error\n";
....
....
untie %hash;

which gives this output:
BDB version: 3.2
Cannot open domains.db:     BDB:

Environment:
- Debian Sarge 3.1
- Exim version 4.50 uid=0 gid=0 pid=12707 D=fbb95dfd
Berkeley DB: Sleepycat Software: Berkeley DB 4.2.52: (December 3,
2003)
Support for: iconv() IPv6 GnuTLS
Lookups: lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmnz
dsearch nis nis0 passwd
...

I've tried to create the database with the perl script (which works
fine) and then access this database with exim but this does not work
either. Is this a version conflict?
Thanks in advance for your help.

Bernd