Organizing your ringtones and assigning it to each user is definitely a handy feature, so let's take a closer look. What is the current software on your device? Please check here: http://spr.ly/6602Esane
When did the issue start? Have you uninstalled and reinstalled the Zedge app? If not, please do so and keep us updated on the results.
Please note that the Zedge app is a third party application so we can walk through general troubleshooting. If the issue is deemed an app issue, you will have to contact the app developers directly. You can do so here: http://spr.ly/6609Esanl (go to the Developer section)