What virus protection do you use? Some Virus protection programs with active scan have problems with youtube. Avast! has this problem, I think.
Also, do you have any plugins that download flash objects, or a Greasemonkey script that does something similar? For instance, if you have Download Helper, it may be set to download flash files from web pages automatically, so it tries to capture every youtube vid you encounter.
If you do happen to have Download Helper, and don't want to disable/uninstall it, then you have to change its settings.
Capture -> Galleries -> Disable "Gallery method"
Edit - Yeah, just saw the Download Helper icon on your Firefox. Change the settings and you should be fine. Tell me if you have any problems after.
Also, do you have any plugins that download flash objects, or a Greasemonkey script that does something similar? For instance, if you have Download Helper, it may be set to download flash files from web pages automatically, so it tries to capture every youtube vid you encounter.
If you do happen to have Download Helper, and don't want to disable/uninstall it, then you have to change its settings.
Capture -> Galleries -> Disable "Gallery method"
Edit - Yeah, just saw the Download Helper icon on your Firefox. Change the settings and you should be fine. Tell me if you have any problems after.