Before getting too deep here, are you running the latest versions of WordPress, themes, and plugins?
#1 Fix - Most Common Issues
Custom Bulk/Quick Edit
- Go to WordPress > Appearance > Themes
- Activate WordPress theme TwentyTwelve
- If URLs work, then you have a theme conflict and should ask your themer to debug further
- Else, apply #2 Fix
- Go to WordPress > Plugins
- Deactivate other plugins one at a time
- After each deactivation, try to repeat the error. If still there, repeat #2 Fix process
- Once you find the plugin conflict, email firstname.lastname@example.org with the information
Check out the video for How to Correct Testimonials Widget CSS Issues.