The fastest would be probably php itself, but you need to be careful with security. Quick and dirty, but not the best options for future, if you want to extend your project.

If you want learn something new and you have time, a framework would be the best. When you have experience with zf use it, it's easier for you to get started.

The middle way would be laravel. It has a really low learning curve and you should be able to learn the basics for your specific project in a day. It shouldn't be a great deal.

If you have any questions to laravel, eg how to deal with uploads, just ask here. There are a lot of helpful people.

For a quick start you can use this starter kit https://github.com/brunogaspar/laravel4-starter-kit including user management, you will expand only for upload file

And laravel already handle file uploading with very easy http://laravel.com/docs/requests#files