ldapsearch with substring problem in my attributes!

["Mauricio Alarcon" <mauricio.alarcon@tecnovas.com>]

Hello
I try to use a filter like
./ldapsearch -D "cn=oseguridad, dc=tecnovas, dc=com" -z 100 -W "(cn=*LP*)"
cn nombres
And works fine, but when I try to use a filter with some of our,attributes
defined in our schema it doesn't work.  I mean (nombres=*a*) , why??

This my attribute defined in ourschema, what's wrong with it??

attributetype ( 2.5.6.1.9
        NAME 'nombres'
        DESC 'Nombres Completos Usuarios PAC'
        EQUALITY caseIgnoreMatch
        ORDERING caseIgnoreOrderingMatch
        SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )
Any ideas will be welcome!
Thanks
  Mauricio

Thanks