[Serusers] ser segfault in function lookup()

[markus monka]

I made a copy of the location table for users having a mailbox.

While getting the data from the Database, 
ser crashes.

ser.cfg
-----
if ( lookup(voicemail) ) {

}

syslog(DEBUG 10)
-----
Oct  3 13:48:39 ser04 /usr/sbin/ser[16453]: query="select
username,contact,expires,q,callid,cseq,replicate,state,flags,user_agent
from voicebox "
Oct  3 13:48:59 ser04 exiting on signal 15

strace -f
-----
18845 read(4, "\0078702713\30sip:123456 at 217.11.29.3"...,69)=69
18845 read(4, "\1\0\0\275", 4)          = 4
18845 read(4, "\376", 1)                = 1
18845 --- SIGSEGV (Segmentation fault) ---
18845 +++ killed by SIGSEGV +++

DB has 5299 rows.

some of the Callids are "NULL". After updating the Entry for Callid with
a random
Id ser starts as usual.

Any Ideas?

Greets 
Markus