Thanks for the link Michael. I had already read it and it was very useful.
I wanted to configure the Liferay, Documents and Media portlet, for use with Amazon S3. This Liferay site says that a SAXParser needs to be configured ...
USING AMAZON SIMPLE STORAGE SERVICE
Amazon’s simple storage service (S3) is a cloud-based storage solution that you can use with Liferay Portal. All you need is an account, and you can store your documents to the cloud from all nodes, seamlessly.
When you sign up for the service, Amazon assigns you unique keys that link you to your account. In Amazon’s interface, you can create “buckets” of data optimized by region. Once you’ve created these to your specifications, use these instructions to connect your S3 account to Liferay Portal.
If you are using Tomcat as your app server, it doesn’t contain a SAXParser. You must include this property in system-ext.properties:
Other app servers also need this configuration if they don’t contain a SAXParser. Remember to place your system-ext.properties file in a folder that resides in your Liferay Portal installation’s class path (e.g., /WEB-INF/classes/).
WHAT I HAVE DONE:
I created a file in this path...
I added the following lines, as suggested by Liferay ...
Thank you for any help or reassurance that I've done the correct thing.