unishare help!!!!

Hi, i am currently using the [8826-screen+shot+2013-03-12+at+10.50.57+am.png|8826]. When i give the callback url as " http://www.facebook.com/" , then no error comes, but it wont authenticate the user. if i give anything other than the above said url, then this error comes and also wont authenticate the user. I have been searching for this for the past two days. Please someone help me . What needs to be in place of the call back url. Thanks a lot in advance.

Please see facebook registry guide: http://unisharekit.com/facebook_reg
Check your site url in your app setting. Make sure you are using the same value in unishare.