"Object Reference not set to an instance of an object." when trying to edit users in FBA User Management

Topics: FBA, Forms Based Authentication, SharePoint
May 7, 2014 at 8:59 AM
Edited May 7, 2014 at 9:29 AM

So we had to restore our server yesterday to the previous state. After performing restore everything seems to work fine besides editing our users in FBA User Management. When I try to do so I get following error message: "Object Reference not set to an instance of an object".
I checked and we have forms authentication set in IIS and Central Administration in Authentication Providers. All users are visible and we can create them in IIS and add them to the web app without problems.
Please help!

May 12, 2014 at 8:57 AM
Just another thing I noticed.
If I create new user in FBA Management there is no problem with editing that user. This problem only occurs when I try to access edit page of existing users, that we had before restore.
I forgot to mention that we are running our platform on SharePoint WSS 3.0.
May 12, 2014 at 10:23 AM
Timestamp Process TID Area Category EventID Level Message Correlation
05/12/2014 11:20:50.30 CKS.FormsBasedAuthentication, V (0x1BA8) 0x1B10 InternetExtranetEdition System.NullReferenceException 0 Critical Object reference not set to an instance of an object. at CKS.FormsBasedAuthentication.UserEdit.OnLoad(EventArgs e) e71821ff-2bae-49c5-a11a-a8eee394c4a5

This is output from logs of my web app