error deleting user after upgrading

[aleph]

hi,

i've upgraded ebox 1.2 to 1.4 a couple of months ago and after that, i'd a problem when i try to delete a user, i've updated every module and installed all the system updates. ebox reports version 1.4.9. I know i should be udating to zentyal, but it's a big deal since there is no upgrade mechanism and i'd bet that it won't resolve this issue,

the web console gives me this error ONLY when i deleted users created with version 1.2. new users after the upgrade can be deleted.

A really nasty bug has occurred
Exception
Unknown error at EBox::Ldap::delObjectclass attribute 'AstVoicemailDelete' not allowed
Trace
Unknown error at EBox::Ldap::delObjectclass attribute 'AstVoicemailDelete' not allowed at /usr/share/perl5/EBox/Ldap.pm line 719
EBox::Ldap::_errorOnLdap('Net::LDAP::Modify=HASH(0xacd480c)', 'HASH(0xac51fd0)') called at /usr/share/perl5/EBox/Ldap.pm line 380
EBox::Ldap::modify('EBox::Ldap=HASH(0x9e4c7b8)', 'uid=jlarsen,ou=Users,dc=ebox', 'HASH(0xac51fd0)') called at /usr/share/perl5/EBox/Ldap.pm line 495
EBox::Ldap::delObjectclass('EBox::Ldap=HASH(0x9e4c7b8)', 'uid=jlarsen,ou=Users,dc=ebox', 'AsteriskVoiceMail') called at /usr/share/perl5/EBox/AsteriskLdapUser.pm line 219
EBox::AsteriskLdapUser::_delUser('EBox::AsteriskLdapUser=HASH(0xabbb6e0)', 'jlarsen') called at /usr/share/perl5/EBox/UsersAndGroups.pm line 1017
EBox::UsersAndGroups::_cleanUser('EBox::UsersAndGroups=HASH(0x96adca0)', 'jlarsen') called at /usr/share/perl5/EBox/UsersAndGroups.pm line 1039
EBox::UsersAndGroups::delUser('EBox::UsersAndGroups=HASH(0x96adca0)', 'jlarsen') called at /usr/share/perl5/EBox/CGI/UsersAndGroups/Del.pm line 88
EBox::CGI::UsersAndGroups::Del::_process('EBox::CGI::UsersAndGroups::Del=HASH(0x85e0100)') called at /usr/share/perl5/EBox/CGI/Base.pm line 263
EBox::CGI::Base::run('EBox::CGI::UsersAndGroups::Del=HASH(0x85e0100)') called at /usr/share/perl5/EBox/CGI/Run.pm line 120
EBox::CGI::Run::run('EBox::CGI::Run', 'UsersAndGroups/Del', 'EBox') called at /usr/share/ebox/cgi/ebox.cgi line 19
ModPerl::ROOT::ModPerl::Registry::usr_share_ebox_cgi_ebox_2ecgi::handler('Apache2::RequestRec=SCALAR(0x8f7fc04)') called at /usr/lib/perl5/ModPerl/RegistryCooker.pm line 204
eval {...} called at /usr/lib/perl5/ModPerl/RegistryCooker.pm line 204
ModPerl::RegistryCooker::run('ModPerl::Registry=HASH(0x8f7fca0)') called at /usr/lib/perl5/ModPerl/RegistryCooker.pm line 170
ModPerl::RegistryCooker::default_handler('ModPerl::Registry=HASH(0x8f7fca0)') called at /usr/lib/perl5/ModPerl/Registry.pm line 31
ModPerl::Registry::handler('ModPerl::Registry', 'Apache2::RequestRec=SCALAR(0x8f7fc04)') called at -e line 0
eval {...} called at -e line 0

any ideas? thanks in advance