I'm seeing the same issue. I guess there's something wrong in our LDAP database or in the config files pointing to it.
In my case, in addition to the messages you see, I'm getting a segfault:
# gdb --args /usr/sbin/asterisk -f
GNU gdb (GDB) 7.1-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/sbin/asterisk...(no debugging symbols found)...done.
(gdb) run
Starting program: /usr/sbin/asterisk -f
[Thread debugging using libthread_db enabled]
[New Thread 0x7ffff7feb700 (LWP 21817)]
[New Thread 0x7ffff7f6f700 (LWP 21818)]
[New Thread 0x7ffff7ef3700 (LWP 21819)]
[New Thread 0x7ffff6005700 (LWP 21820)]
[New Thread 0x7ffff5f89700 (LWP 21821)]
[Jun 5 15:48:26] NOTICE[21814]: cdr.c:1558 do_reload: CDR simple logging enabled.
[New Thread 0x7ffff5f0d700 (LWP 21822)]
[New Thread 0x7ffff5e91700 (LWP 21823)]
[New Thread 0x7ffff5e15700 (LWP 21824)]
[New Thread 0x7ffff5d99700 (LWP 21825)]
[New Thread 0x7ffff5d1d700 (LWP 21826)]
[New Thread 0x7ffff5ca1700 (LWP 21827)]
[Jun 5 15:48:26] NOTICE[21814]: loader.c:1135 load_modules: 222 modules will be loaded.
[Jun 5 15:48:28] NOTICE[21814]: res_odbc.c:1889 load_module: res_odbc loaded.
[Jun 5 15:48:28] NOTICE[21814]: res_smdi.c:1418 load_module: No SMDI interfaces are available to listen on, not starting SMDI listener.
[New Thread 0x7ffff3dff700 (LWP 21828)]
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1484 load_mysql_config: MySQL RealTime: No database user found, using 'asterisk' as default.
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1490 load_mysql_config: MySQL RealTime: No database password found, using 'asterisk' as default.
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1496 load_mysql_config: MySQL RealTime: No database host found, using localhost via socket.
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1502 load_mysql_config: MySQL RealTime: No database name found, using 'asterisk' as default.
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1508 load_mysql_config: MySQL RealTime: No database port found, using 3306 as default.
[Jun 5 15:48:44] WARNING[21814]: res_config_mysql.c:1525 load_mysql_config: MySQL RealTime: No database socket found (and unable to detect a suitable path).
[Jun 5 15:48:44] NOTICE[21814]: config.c:2201 ast_config_engine_register: Registered Config Engine mysql
[Jun 5 15:48:44] NOTICE[21814]: config.c:2201 ast_config_engine_register: Registered Config Engine sqlite
[Jun 5 15:48:44] NOTICE[21814]: config.c:2201 ast_config_engine_register: Registered Config Engine curl
[Jun 5 15:48:45] NOTICE[21814]: config.c:2201 ast_config_engine_register: Registered Config Engine ldap
[New Thread 0x7fffcd777700 (LWP 22036)]
[Jun 5 15:48:45] WARNING[21814]: chan_sip.c:28674 reload_config: No valid transports available, falling back to 'udp'.
[New Thread 0x7fffcd6fb700 (LWP 22037)]
[New Thread 0x7fffcd57d700 (LWP 22038)]
[New Thread 0x7fffcd501700 (LWP 22039)]
[New Thread 0x7fffcd485700 (LWP 22040)]
[New Thread 0x7fffcd409700 (LWP 22041)]
[New Thread 0x7fffcd38d700 (LWP 22042)]
[New Thread 0x7fffcd311700 (LWP 22043)]
[New Thread 0x7fffcd295700 (LWP 22044)]
[New Thread 0x7fffcd219700 (LWP 22045)]
[New Thread 0x7fffcd19d700 (LWP 22046)]
[New Thread 0x7fffcd121700 (LWP 22047)]
[New Thread 0x7fffcd0a5700 (LWP 22048)]
[New Thread 0x7fffcd029700 (LWP 22049)]
[New Thread 0x7fffccfad700 (LWP 22050)]
[New Thread 0x7ffff7e77700 (LWP 22051)]
[New Thread 0x7fffccb1d700 (LWP 22052)]
[New Thread 0x7fffccadc700 (LWP 22053)]
[New Thread 0x7fffcca60700 (LWP 22054)]
[Jun 5 15:48:45] NOTICE[21814]: chan_skinny.c:7220 config_load: Configuring skinny from skinny.conf
[New Thread 0x7fffcc9e4700 (LWP 22055)]
[New Thread 0x7fffcc968700 (LWP 22056)]
[Jun 5 15:48:45] NOTICE[21814]: cel_tds.c:452 tds_load_module: cel_tds has no global category, nothing to configure.
[Jun 5 15:48:45] WARNING[21814]: cel_tds.c:557 load_module: cel_tds module had config problems; declining load
[Jun 5 15:48:45] NOTICE[21814]: cdr_pgsql.c:390 config_module: cdr_pgsql configuration contains no global section, skipping module load.
[Jun 5 15:48:45] WARNING[21814]: cel_pgsql.c:390 process_my_load_module: CEL pgsql config file missing global section.
[New Thread 0x7fffcc8ec700 (LWP 22057)]
[New Thread 0x7fffcc870700 (LWP 22058)]
[New Thread 0x7fffcc7f4700 (LWP 22059)]
[New Thread 0x7fffcc778700 (LWP 22060)]
[Jun 5 15:48:45] ERROR[21814]: ais/clm.c:140 ast_ais_clm_load_module: Could not initialize cluster membership service: Try Again
[New Thread 0x7fffcc6fc700 (LWP 22061)]
[Jun 5 15:48:45] ERROR[21814]: chan_vpb.cc:2672 ast_module_load_result load_module(): No Voicetronix cards detected
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:164 pbx_load_module: Starting AEL load process.
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:177 pbx_load_module: AEL load process: parsed config file name '/etc/asterisk/extensions.ael'.
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:180 pbx_load_module: AEL load process: checked config file name '/etc/asterisk/extensions.ael'.
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:187 pbx_load_module: AEL load process: compiled config file name '/etc/asterisk/extensions.ael'.
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:192 pbx_load_module: AEL load process: merged config file name '/etc/asterisk/extensions.ael'.
[Jun 5 15:48:45] NOTICE[21814]: pbx_ael.c:195 pbx_load_module: AEL load process: verified config file name '/etc/asterisk/extensions.ael'.
[New Thread 0x7fffcc680700 (LWP 22062)]
[New Thread 0x7fffcc604700 (LWP 22063)]
[New Thread 0x7fffcc588700 (LWP 22064)]
[New Thread 0x7fffcc50c700 (LWP 22065)]
[New Thread 0x7fffcc490700 (LWP 22066)]
[New Thread 0x7fffcc414700 (LWP 22072)]
[New Thread 0x7fffcc398700 (LWP 22073)]
[Thread 0x7fffcc414700 (LWP 22072) exited]
[New Thread 0x7fffcc414700 (LWP 22075)]
[Jun 5 15:48:56] WARNING[22075]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22075) exited]
[New Thread 0x7fffcc414700 (LWP 22080)]
[Jun 5 15:49:00] WARNING[22080]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22080) exited]
[New Thread 0x7fffcc414700 (LWP 22084)]
[Jun 5 15:49:04] WARNING[22084]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22084) exited]
[New Thread 0x7fffcc414700 (LWP 22085)]
[Jun 5 15:49:07] WARNING[22085]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22085) exited]
[New Thread 0x7fffcc414700 (LWP 22086)]
[Jun 5 15:49:10] WARNING[22086]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22086) exited]
[New Thread 0x7fffcc414700 (LWP 22087)]
[Jun 5 15:49:14] WARNING[22087]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22087) exited]
[New Thread 0x7fffcc414700 (LWP 22088)]
[Jun 5 15:49:17] WARNING[22088]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
[Thread 0x7fffcc414700 (LWP 22088) exited]
[New Thread 0x7fffcc414700 (LWP 22089)]
[Jun 5 15:49:21] WARNING[22089]: res_config_ldap.c:967 realtime_multi_ldap: realtime retrieval requires at least 1 parameter and 1 value to search on.
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffcc414700 (LWP 22089)]
0x00007ffff74fa2a2 in ?? () from /lib/libc.so.6
(gdb) bt
#0 0x00007ffff74fa2a2 in ?? () from /lib/libc.so.6
#1 0x00007fffcf192681 in ?? () from /usr/lib/asterisk/modules/res_config_ldap.so
#2 0x0000000000475b9c in ast_load_realtime_multientry ()
#3 0x00007ffff1aede30 in ?? () from /usr/lib/asterisk/modules/pbx_realtime.so
#4 0x00007ffff1aedfc7 in ?? () from /usr/lib/asterisk/modules/pbx_realtime.so
#5 0x00000000004dc028 in pbx_find_extension ()
#6 0x00000000004deb5f in ?? ()
#7 0x00000000004e0094 in ast_exists_extension ()
#8 0x00000000004e0486 in ?? ()
#9 0x00000000004e175b in ?? ()
#10 0x000000000051a56a in ?? ()
#11 0x00007ffff6b079ca in start_thread () from /lib/libpthread.so.0
#12 0x00007ffff755dcdd in clone () from /lib/libc.so.6
#13 0x0000000000000000 in ?? ()
(gdb)
