CentOS 7 (Apache2) Cannot Install SSL Cert

Hi All

I've purchased an SSL cert for my website.

I've create folder called 'localcerts' in my etc/ssl folder.
I've coped into that folder the Cert, the Key File, All the Root and Intermediate Certs.
I've created a ca.pem file by running cat on the certs like so

cat COMODORSADomainValidationSecureServerCA.crt COMODORSAAddTrustCA.crt AddTrustExternalCARoot.crt > ca.pem

I've edited the httpd.conf and tagged this on the end;

<VirtualHost *:443>
     SSLEngine On
     SSLCertificateFile /etc/ssl/localcerts/www_pnl_com.crt
     SSLCertificateKeyFile /etc/ssl/localcerts/www.pnl.com.key
     SSLCACertificateFile /etc/ssl/localcerts/ca.pem

     ServerAdmin information@pnl.com
     ServerName www.pnl.com
     DocumentRoot /var/www/html
     ErrorLog /var/www/logs/error.log
     CustomLog /var/www /logs/access.log combined
</VirtualHost>

But then apache refuses to start

I've tried replacing the PEM file with the intermediate CA Cert like so

     SSLCACertificateFile /etc/ssl/localcerts/COMODORSADomainValidationSecureServerCA.crt

Same result?

I don't know enough about Linux to troubleshoot the problem? Can anyone see what I'm doing wrong? Or can you suggest a better approach?

Pete