when I close the browers or try to close the browers, I get this message "unresponsive script", the browers will not close and I am forced to close it, where I get a second message, "plugin container for firefox has stopped working", how do I fix this??

browers will not close, gives error message(s): unresponsive script, plugin container for firefox has stopped working.

The unresponsive script error happens everytime I try to close the browser, then when I shut down the browser by hitting the "x" button a couple of times I get the second message.