User Username not found in membership store does not exist - asp.net-membership

Question

Within our community server site, when I navigate to the UserList.aspx page, I get the following error every time: User Not Found, The user you requested cannot be found.
When I check the event log, I see asp.net warnings as follows:
Event Type: Warning
Event Source: ASP.NET 2.0.50727.0
Event Category: Web Event
Event ID: 1309
Date: 4/17/2013
Time: 9:39:43 AM
User: N/A
Computer: SV3369
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 4/17/2013 9:39:43 AM
Event time (UTC): 4/17/2013 2:39:43 PM
Event ID: f121eb3cd0a847b2a53972a09f802235
Event sequence: 11116
Event occurrence: 1072
Event detail code: 0
Application information:
Application domain: /LM/W3SVC/8022/ROOT-1-130105941980617500
Trust level: Full
Application Virtual Path: /
Application Path: C:\Inetpub\wwwroot\wisdomresearch.org\wwwroot\
Machine name: SV3369
Process information:
Process ID: 4148
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE
Exception information:
Exception type: CSException
Exception message: User Username not found in membership store does not exist.
Request information:
Request URL: http://wisdomresearch.org/themes/basic/Arete/UserList.aspx?interest=European+History
Request path: /themes/basic/Arete/UserList.aspx
User host address: 173.199.116.83
User:
Is authenticated: False
Authentication Type:
Thread account name: NT AUTHORITY\NETWORK SERVICE
Thread information:
Thread ID: 8
Thread account name: NT AUTHORITY\NETWORK SERVICE
Is impersonating: False
Stack trace: at CommunityServer.Users.AddMembershipDataToUser(UserSet users)
at CommunityServer.Users.GetUsers(UserQuery query, Boolean cacheable)
at Arete.Common.GetGlobalUsersTable()
at PageBase.GetUsersTableFromCache()
at Themes_basic_Arete_userlist.BindUsers()
at Themes_basic_Arete_userlist.ExecuteSearch()
at Themes_basic_Arete_userlist.Page_Load()
at System.Web.Util.CalliHelper.ArglessFunctionCaller(IntPtr fp, Object o)
at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
at System.Web.UI.Control.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Also, I've seen this post, but I'm unsure of what I need to do if this is my problem.

Answer 1

First of all, I'm not familiar with community server site, although I used ASP.Net Membership extensively.
According to the SO link in your question, the problem is users are missing in cs_Users table (or might be other table).
1 - You need to find those orphaned rows. Something like this -
SELECT * FROM aspnet_Users WHERE UserId NOT IN (SELECT UserId FROM cs_Users)
2 - Then you either need to delete them or do something.