当我 create a user from the web site administration tool provided by Asp.NET.时抛出异常：
The following message may help in diagnosing the problem: Exception has been
thrown by the target of an invocation. at
System.RuntimeMethodHandle._InvokeMethodFast(Objec t target, Object[]
arguments, SignatureStruct& sig, MethodAttributes methodAttributes,
RuntimeTypeHandle typeOwner) at
System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[]
arguments, Signature sig, MethodAttributes methodAttributes,
RuntimeTypeHandle typeOwner) at
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags
invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean
skipVisibilityChecks) at System.Reflection.RuntimeMethodInfo.Invoke(Object
obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo
culture) at
System.Web.Administration.WebAdminMembershipProvid er.CallWebAdminMembershipProviderHelperMethodOutPa rams(String
methodName, Object[] parameters, Type[] paramTypes) at
System.Web.Administration.WebAdminMembershipProvid er.CreateUser(String
username, String password, String email, String passwordQuestion, String
passwordAnswer, Boolean isApproved, Object providerUserKey,
……………………
去google 了一下没有什么结果，不过在一个英文站点发现有人说关于数据库lock的可能性，于是发现自己使用的是一个示例站点，里面已经存在了ASPNETDB，尝试着删除这个数据库并重新建立成员即可。
This is the answer from "mlotfi" :
If you are copying the project from another computer (downloaded), to solve the problem just delete ASPNETDB from App_data, and go to website--> ASP.NET Configuration and add a new user.