DSfW (OES11SP1) and Clariion Celerra (CIFS Share)

Filer Head can not join DSfW Domain:

ErrorTue Nov 20 09:52:10 CET 2012ADMINCommand failed: domjoin compname=fhbtest.dsfw.fh-brandenburg.de domain=DSFW.FH-BRANDENBURG.DE admin=Administrator password=************************** ou="ou=wirtschaft"init
ErrorTue Nov 20 09:52:10 CET 2012SMBDomainJoin::verifyDomain: Specified domain'DSFW.FH-BRANDENBURG.DE'does not match domain name reported by Active Directory server fhs-dsfw1.dsfw.fh-brandenburg.de
ErrorTue Nov 20 09:52:10 CET 2012SMBDomainJoin compname=fhbtest domain=DSFW.FH-BRANDENBURG.DE DC=fhs-dsfw1.dsfw.fh-brandenburg.de IP= failed

Note: ou="ou=wirtschaft"init this is not a typo, 'tranlated' by GUI mask and
a network trace on DSfW 'PDC' show some DNS, LDAP Domain queries but no errors, Domain Name reported are fine.
on storage console Domain info is also fine (NetBIOS and FQDN):

[root@NS1w118 log]# /nas/bin/server_cifs server_2
server_2 :
DOMAIN DSFW FQDN=dsfw.fh-brandenburg.de SITE=Default-First-Site-Name
>DC=FHS-DSFW1( ref=3 time=9 ms (Closest Site)
but RC=4 ??

W2008R2 join --> DSfW success
clariion --> MS 2003 Domain success

any ideas ??

Call at NOVELL and EMC are open, but ...