amavisd-new panics randomly

[Bánhalmi Csaba via amavis-users]

Hi all,

I have a FreeBSD 10.0-RELEASE system with postfix+amavisd-new+clamav. 
amavisd-new has MySQL backend, spamassassin is not running in daemon 
mode. A couple days ago amavisd started to panic randomly, in amavis.log 
I see tons of this:

May 23 18:12:34 domain.hu /usr/local/sbin/amavisd[25492]: (!)_DIE: Suicide in child_init_hook: BDB no dbS: Lock table is out of available locker entries, . at (eval 107) line 31.
May 23 18:12:34 domain.hu /usr/local/sbin/amavisd[25494]: (!)_DIE: Suicide in child_init_hook: BDB no dbS: Lock table is out of available locker entries, . at (eval 107) line 31.
May 23 18:12:34 domain.hu /usr/local/sbin/amavisd[25493]: (!)_DIE: Suicide in child_init_hook: BDB no dbS: Lock table is out of available locker entries, . at (eval 107) line 31.
May 23 18:12:34 domain.hu /usr/local/sbin/amavisd[25495]: (!)_DIE: Suicide in child_init_hook: BDB no dbS: Lock table is out of available locker entries, . at (eval 107) line 31.
May 23 18:12:34 domain.hu /usr/local/sbin/amavisd[25496]: (!)_DIE: Suicide in child_init_hook: BDB no dbS: Lock table is out of available locker entries, . at (eval 107) line 31.

When I try to restart the amavisd-new service manually (/usr/local/etc/rc.d/amavisd restart) I see this in log and amavisd-new cannot start:
May 28 06:30:19 cool.prograph.hu /usr/local/sbin/amavisd[8859]: (!)Net::Server: 2014/05/28-06:30:19 Unable to load module for proto "Net::Server::Proto::UNIX": Can't locate Net/Server/Proto/UNIX.pm: Permission denied at
/usr/local/lib/perl5/site_perl/5.18/Net/Server/Proto.pm line 198.\n\n  at line 198 in file /usr/local/lib/perl5/site_perl/5.18/Net/Server/Proto.pm

I have to wait 30 minutes or restart the server to start amavisd again. As far as I know BDB is used by amavis in /var/amavis/db:
-rw-r-----   1 vscan  vscan   24576 May 28 06:33 __db.001
-rw-r-----   1 vscan  vscan   65536 May 28 06:33 __db.002
-rw-r-----   1 vscan  vscan  270336 May 28 06:33 __db.003
-rw-r-----   1 vscan  vscan  753664 May 28 06:33 __db.004
-rw-r-----   1 vscan  vscan   49152 May 28 11:04 nanny.db
-rw-r-----   1 vscan  vscan   49152 May 28 11:04 snmp.db

In amavisd.conf I have these regarding the BDB:
$enable_db = 1;              # enable use of BerkeleyDB/libdb (SNMP and nanny)
$enable_global_cache = 1;    # enable use of libdb-based cache if $enable_db=1
$nanny_details_level = 2;    # nanny verbosity: 1: traditional, 2: detailed


Can you give me a hint where should I look, what should I do? Not sure what does it mean "BDB no dbS"

Thank you and Best Regards,
Csaba