That is a bug with blocklisting plugins that has been fixed.
You can correct this issue by forcing the file blocklist.xml to update or wait until Firefox updates the file.
That update will remove the severity="0" flags in the file that cause the problem.

See:

• /questions/832793?page=2#answer-198407
• http://forums.mozillazine.org/viewtopic.php?p=10899869#p10899869

• Bug 663722 - The blocklist output is including severity="0" where it shouldn't be

i have had this problem for about 2 weeks... the update plugins message is there nite and day! i go to the site to update them. It says update quicktime player or sth. I press the download button. It downloads. Turn off pc. Turn it on: back to square 1....says update plugins... I am not a pc expert. I don't understand what the answer above means?? How on earth do i force the file blocklist to update...etc etc etc ..that sounds like alien speak.. i use a chat site and it keeps crashing... is that to do with this plug in thing? can anyone help me.... (i mean tell me in english what to do?) thx

@rhian

Please start a new thread for your problem or question and provide troubleshooting information like your operating system and installed extensions and installed plugins.

• [start a new thread]
• [/kb/Using+the+Troubleshooting+Informatio...]

[locking thread due to the age]