<b>about:config</b> is without any spaces in it. *http://kb.mozillazine.org/about:config To open the <i>about:config</i> page, type <b>about:config</b> in the location (address) bar and press the "<i>Enter</i>" key, just like you type the url of a website to open a website.<br /> If you see a warning then you can confirm that you want to access that page.<br /> *Use the Filter bar at to top of the about:config page to locate a preference more easily. *Preferences that have been modified show as bold (user set). *Preferences can be reset to the default via the right-click context menu if they are user set *Preferences can be changed via the right-click context menu: Modify (String or Integer) or Toggle (Boolean)

I don't find dom.successive_dialog_time_limit in FF 9.0.1