Hi Nagarajan,
Comments are inline below:
>> 1) To avoid this error in the browser do I need to generate a csr that is similar to the existing one(shibIDP.csr)
No.
>> get this signed by a central CA and and import them into the corresponding key store?
Yes.
>> Do I need to replace files like shibIDP.csr, shibIDP.crt?
No.
>> What is the use of other keystore and crt files those are there in etc/certs?
* httpd.key and httpd.crt: these are for your Gluu Server's apache cert.
* shibIDP.key and shibIDP.crt: these are for your Gluu Server's SAML part.
As you are getting complain from your browser so you need to apply CA-signed cert in httpd.key and httpd.crt.
Feel free to check [this](http://www.gluu.org/docs/admin-guide/certificates/)
wiki.
Let us know how it is going there.
Kind regards,
Zico