L1b extension filed recieved a rfe .

I recieved a rfe will it be considered unlawful stay incase my extension gets rejected?If i reply & wait for response & incase if my petition is denied ,will this affect in my future visa approvals .My I-94 is expiring on feb 20 2013

Usually you are considered in illegal status for any stay after the extension petition has been denied. So you can stay while the petition is still under process. But if it gets denied, then you should leave ASAP. You should also leave US if the petition is still pending and it has been more than 240 days since your I-94 expired.

It should not impact future immigration petitions. Do keep copy of extension filing and final decision to show that extension was timely filed and what date it was denied.