Here is the search that Apache is doing. Note that "usuarios" in the search means "users" in portuguese. It doesn't seems even to check if the user really does part of the group defined in the apache config.
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=0 BIND dn="cn=root,dc=dominio,dc=com,dc=br" method=128
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=0 BIND dn="cn=root,dc=dominio,dc=com,dc=br" mech=SIMPLE ssf=0
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=0 RESULT tag=97 err=0 text=
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=1 SRCH base="ou=Usuarios,dc=dominio,dc=com,dc=br" scope=2 deref=3 filter="(&(objectClass=*)(uid=lscarneiro))"
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=1 SRCH attr=uid
Feb 17 11:11:39 fileserver slapd[2054]: <= bdb_equality_candidates: (uid) not indexed
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=1 ENTRY dn="uid=lscarneiro,ou=usuarios,dc=dominio,dc=com,dc=br"
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=1 SEARCH RESULT tag=101 err=0 nentries=1 text=
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=2 BIND anonymous mech=implicit ssf=0
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=2 BIND dn="uid=lscarneiro,ou=Usuarios,dc=dominio,dc=com,dc=br" method=128
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=2 RESULT tag=97 err=49 text=
Feb 17 11:11:39 fileserver slapd[2054]: conn=1014 op=3 UNBIND