CA SiteMinder - Apache WebAgent Restart fails

Environment

Apache 2.2.15
OS: Redhat Linux 6.4
webagent version: r12.51 Cr03

Issue:

Apache restart failed with the below error after the successful webagent installation and configuration.

[user@server1# service httpd start

Starting httpd: httpd: Syntax error on line 150 of /etc/httpd/conf/httpd.conf: Cannot load /opt/CA/webagent/bin/libmod_sm22.so into server: libsmerrlog.so: cannot open shared object file: No such file or directory                                                       [FAILED]

Used the below commands to stop and start the Apache server during the failure,

service httpd stop

service httpd start

Solution:

Using the below command, i was able to restart the Apache server without any issue. 

apachectl -k start

apachectl -k stop

Did not perform any other configuration changes in Apache or webagent to fix this issue. Really not sure on the differences between these 2 types of commands.