ch_calloc of 1 elems of 0 bytes failed (ITS#2865)

[lalot@univ-aix.fr]

Full_Name: LALOT Dominique
Version: 2.1.23
OS: linux 2.4.9-13smp
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (193.50.125.2)


Dec  8 10:17:54 annuaire slapd[16489]: conn=294 op=1 SRCH
base="ou=people,ou=etudiant,ou=u2,dc=univ-mrs,dc=fr" scope=2 filter="(uid=x*)"
Dec  8 10:17:54 annuaire slapd[16489]: <= bdb_substring_candidates: (uid)
index_param failed (18)
Dec  8 10:17:55 annuaire slapd[16489]: ch_calloc of 1 elems of 0 bytes failed

Then slapd died.
changed from uid=x* to cn=x* without success

2 databases on same server:
database bdb
suffix "ou=etudiant,ou=u2,dc=univ-mrs,dc=fr"

database bdb
suffix      "ou=u2,dc=univ-mrs,dc=fr"

1GB of RAM

Index and base are regenerated from ldif each week.
BDB 4.1.25NC, backend BDB
index uid,uidNumber,gidNumber,u2codeetud,u2codeetape eq,pres
index cn,surname     pres,eq,subany

Help please!.

Thanks