[389-users] Authentication failed because the server was unable to generate authentication credentials. The authentication database could not be opened.

[Maurizio Marini]

thsi was 
already discussed on this thread:

http://lists.fedoraproject.org/pipermail/389-users/2009-April/009362.html

but there was clue to solve the issue.

this server is a CentOS 6 with following packages:

389-admin-1.1.25-1.el6.x86_64
389-ds-console-1.2.6-1.el6.noarch
389-adminutil-devel-1.1.14-2.el6.x86_64
389-ds-base-1.2.9.14-1.el6_2.2.x86_64
389-admin-console-1.1.8-1.el6.noarch
389-dsgw-1.1.7-2.el6.x86_64
389-ds-base-devel-1.2.9.14-1.el6_2.2.x86_64
389-admin-console-doc-1.1.8-1.el6.noarch
389-console-1.1.7-1.el6.noarch
389-ds-base-libs-1.2.9.14-1.el6_2.2.x86_64
389-adminutil-1.1.14-2.el6.x86_64
389-ds-console-doc-1.2.6-1.el6.noarch
389-ds-1.2.2-1.el6.noarch

I have configured dsgw using:
http://directory.fedoraproject.org/wiki/DSGW

when i try to authenticate a test user, using 
/var/log/dirsrv/slapd-ds/access
i see authentication is ok:
[30/Mar/2012:22:30:23 +0200] conn=103 op=1 BIND
dn="uid=xxx,ou=People,dc=xxx,dc=it" method=128 version=3 
[30/Mar/2012:22:30:23+0200] conn=103 op=1 RESULT err=0 tag=97 nentries=0 etime=0
dn="uid=xxx,ou=people,dc=xxx,dc=it"

i use xxx to obfuscate real names to protect my  customer privacy.
but something goes wrong after it, into dsgw
Is there any dsgw log to diagnose better the issue?

regards