need help always get error with Java

[49ers11]

hey guys need help
this the problem i get :
I go to certain websites and I get this error with firefox.

This Site requires that JavaScript be enabled.

It is enabled.

This is the one of the errors in java script console with firefox.

Error: [Exception... "'Component does not have requested interface' when calling method: [nsIInterfaceRequestor::getInterface]" nsresult: "0x80004002 (NS_NOINTERFACE)" location: "<unknown>" data: no]

I have installed the java script from there home site and did a test and says everything is fine. Any ideas?

please help

[JPnyc]

You have not installed javascript. You installed Java. Javascript cannot be downloaded or installed. A browser either supports JS or does not support it. So if you have enabled or disabled Java, it will have no effect whatsoever on whether or not Javascript is enabled or disabled. They're 2 entirely separate technologies. Are you sure javascript is enabled in tools, options, web features?

[49ers11]

yea everything is fine in my web features in FF options.
every thing was fine about 2 months ago!
i dont now what happen and i get this error message

[JPnyc]

Try posting the issue here in the internet software forum. Lots of FF users there that may be able to help. But you probably need to delete and reinstall, and be sure to include the profile when deleting.