PHPRtfLite has been moved to github.com: https://github.com/phprtflite/PHPRtfLite (svn import from trunk). The project has been moved to give the community the ability to get better involved in contributing to the project by forking, making pull requests, and so on.
For issues please use the issue tracker on github.
The site at sourceforge.net will be still available for older releases. I'm not sure, if new versions will also be released at sourceforge, yet.