Discovered this link
- In your url bar type in "about:config" without the quotes.
- Locate the search field at the top of the document and enter: "dom.ipc.plugins.timeoutSecs" without the quotes.
- Double click on that item and set its value to what ever you'd like to increase the amount of time before it considers a plugin hung. 4 NOTE: if you change that value to -1 it should never time out.