Weird error when modifying a single attribute

[Yiannis Mavroukakis]

Hello fellow listers :-)
I've come across an odd issue, while trying to modify a single attribute 
in LDAP.
If I do a wholemeal change of every attribute in my entry it works fine. 
However if I only try to change
the userPassword then it blows up with the following error

3:20:36,026 ERROR [UserActionBean] javax.naming.NamingException: [LDAP: 
error code 80 - OTHER: failed for     Modify Request
       Object : 
'2.5.4.3=imavroukakis,2.5.4.11=player,0.9.2342.19200300.100.1.25=gameaccount,0.9.2342.19200300.100.1.25=com'
           Modification[0]
               Operation :  replace
               Modification
   objectClass: top
   objectClass: person
   objectClass: organizationalPerson
   objectClass: inetOrgPerson
   objectClass: gaPlayer
           Modification[1]
               Operation :  replace
               Modification
   userPassword: '0x22 ...'
           Modification[2]
               Operation :  replace
               Modification
   cn: imavroukakis
: null:  <-- not sure why this is null!!

Any ideas? I am using the latest trunk.

Thanks,

Yiannis