This mozilla support article offers suggestions for resolving the script problem including letting the script run longer. In at least one test scenario, letting the script run longer proved successful in resolving the error.

The problem may occur in the following area:
  1. Academics > People Finder.
  2. Enter a student's record.
  3. Click the Enrollment tab.
  4. Click Manage for any term.
  5. As the page loads, the Warning: Unresponsive Script may occur.