Ok,
Stop the web server with the init script
/etc/rc.d/init.d/httpd first
then try the command i posted.
About the modules:
I think /usr/lib/httpd/libphp4.so is the RPM one.
/home/sandhya.... is the one you compiled
/home/sunil.... is the one compiled by whoever.
Please post the /etc/httpd/httpd.conf file.
One test: stop the web server, then rename /usr/lib/httpd/modules/libphp4.so (so you can restore it.
Then copy /home/sandhya/php-4.3.6/.libs/libphp4.so
to /usr/lib/httpd/ and try to start the web server.
Did you try to reinstall some PHP RPM packages because I don't undestand why the module is php-4.2.2 and your phpinfo page showed php-4.3.6.
Thomas