First you need to update to Firefox 16.0.2, Firefox 3.6 is no longer supported, and not only is vulnerable to a long list of publicly known security issues, has many hundreds of known bugs and issues. Update Firefox to the latest release.

After updating Firefox, try to Reset Firefox if the issue still exists. Refresh Firefox - reset add-ons and settings

If it is not a tab then what does she get (maybe attach a screenshot)?

Is this an unfinished download?

In that case try to delete the downloads.sqlite file in the Firefox Profile Folder.

See:

• http://kb.mozillazine.org/Unable_to_save_or_download_files#Manually_delete_download_history

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder