apache - Unable to set php_value 'soap.wsdl_cache_dir' -

i have vps server (centos 6.5) running apache 2.2.4 , php-fpm (fastcgi process manager). looking in php-fpm error_log i've noticed error every spawn php-fpm child process:

warning: [pool www] child 24086 said stderr: "error: unable set php_value 'soap.wsdl_cache_dir'" 

i couldn't find info on warning googling. aware mean , how rid of warning?

update 1:

fastcgi.conf apache:

user apache                                                                                                                              group apache                                                                                                                              loadmodule fastcgi_module modules/mod_fastcgi.so                                                                                          <ifmodule mod_fastcgi.c>                                                                                                                     directoryindex index.php index.html index.shtml index.cgi                                                                            addhandler php5-fcgi .php                                                                                                            # monitoring status e.g. munin                                                                                              <locationmatch "/(ping|status)">                                                                                                             sethandler php5-fcgi-virt                                                                                                            action php5-fcgi-virt /php5-fcgi virtual                                                                                     </locationmatch>                                                                                                                      action php5-fcgi /php5-fcgi                                                                                                          alias /php5-fcgi /usr/lib/cgi-bin/php5-fcgi                                                                                          fastcgiexternalserver /usr/lib/cgi-bin/php5-fcgi -socket /tmp/php5-fpm.sock -pass-header authorization                           </ifmodule>  # global fastcgiconfig can overridden fastcgiserver options in vhost config                                                        fastcgiconfig -idle-timeout 20 -maxclassprocesses 1 

and here php-fpm.conf , pool configuration php:

pid = /var/run/php-fpm/php-fpm.pid daemonize = yes  ; start new pool named 'www'.                                                                                                          [www]  listen = /tmp/php5-fpm.sock  group = apache pm = dynamic pm.max_children = 8 pm.start_servers = 2 pm.min_spare_servers = 1 pm.max_spare_servers = 3 pm.status_path = /status ping.path = /ping catch_workers_output = yes php_admin_value[error_log] = /var/log/php-fpm/www-error.log                                                                              php_admin_flag[log_errors] = on php_value[session.save_handler] = files                                                                                                  php_value[session.save_path]    = /var/lib/php/session                                                                                   php_value[soap.wsdl_cache_dir]  = /var/lib/php/wsdlcache 

everything else on defaults.

update 2:

after manually creating /var/lib/php/wsdlcache directory suggested , setting permissions 770 , owner root:apache, hoped won't see error again, unfortunately after restarting php-fpm process error there again , becomes strange.

p.s. maybe question more appropriate serverfault, there more experts in php , apache configuration on stackoverflow.

i hate trivial solutions. i've found problem , solution myself. leaving here reference others pre-history.

fastcgi configuration files taken internet when first configuring fastcgi haven't used before. tutorials showing fastcgi configuration contained line php_value[soap.wsdl_cache_dir] = /var/lib/php/wsdlcache. became interested soap don't use on websites run on server , curiosity brought me solution. don't need soap , removing line fix problem guess, i've decided leave there , found out needed install php-soap.

yum install php-soap 

for rhel/centos

after restarting php-fpm don't error on respawning fpm processes.