Server Error in '/' Application.
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Couldn't update database: System.NullReferenceException: Object reference not set to an instance of an object.
at AspDotNetStorefrontCommon.AppConfigs.Add(AppConfig appconfig) in C:\Inetpub\wwwroot\website\ASPDNSFCommon\Appconfig .cs:line 401
at AspDotNetStorefrontCommon.AppConfigs.Add(String Name, String Description, String ConfigValue, String GroupName, Boolean SuperOnly) in C:\Inetpub\wwwroot\Website\ASPDNSFCommon\Appconfig .cs:line 409
at AspDotNetStorefrontAdmin.appconfig.btnInsert_Click (Object sender, EventArgs e) in c:\Inetpub\wwwroot\Website\Web\Development\appconf ig.aspx.cs:line 640

in the event viewer it looks like this:
Event Type: Warning
Event Source: ASP.NET 2.0.50727.0
Event Category: Web Event
Event ID: 1309

How do I fix this