Sounds like you just need a place to store data, a simple web interface, and a basic permissions structure.

In my opinion you should use a database to store the information instead of text files. It's less work ultimately, and won't cause badness if two people save the same item at once.

As for the web interface you should use a templating system instead of writing inline html. It's much cleaner and easier to maintain. Your needs sound fairly basic, so you can get away with using HTML::Template. You should be up and running with it in under 30 minutes, and will never write inline html again. If you're adventurous then Template Toolkit is a more robust option.

As for the perl code to control everything there are a number of frameworks for encapsulating common design patterns. For example, CGI::Application provides the common dispatch script behaviour.