[Serusers] ser segfault in function lookup()

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@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