Hello Carla,
Thank you for the details of the issue you are experiencing with PBS on your Apple TV. I recommend the following steps:
If you have playback issues with a content provider's services
In most cases, you can isolate playback issues to your home network, your broadband connection, or a possible outage with a content provider. To see if your issue is affecting multiple services or a specific content provider, try another service. For example, play a movie trailer from the main menu.
- If the issue is affecting multiple services on your Apple TV, see how to troubleshoot playback performance.
- If the issue is affecting a single content provider on your Apple TV, restart your Apple TV by going to Settings > General > Restart. If the issue continues, you might need to contact the content provider.
Apple TV: Troubleshooting third-party content providers
http://support.apple.com/kb/TS5374
Thank you for using Apple Support Communities.
Best,
Sheila M.