are there duplicate entries for the same portal?

I'm also getting this message when reseting a user password 'The password has been reset, but there was an error sending the Email reminder message.' Not sure if this is also related to this issue.

Here is the general exception for the log viewer:

InnerException: Object reference not set to an instance of an object.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: DotNetNuke.Entities.Users.UserInfo.GetProperty
StackTrace:
Message: System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Entities.Users.UserInfo.GetProperty(String strPropertyName, String strformat, CultureInfo formatProvider, UserInfo AccessingUser, Scope CurrentScope, Boolean& PropertyNotFound) at DotNetNuke.Services.Tokens.BaseCustomTokenReplace.replacedTokenValue(String strObjectName, String strPropertyName, String strformat) at DotNetNuke.Services.Tokens.BaseTokenReplace.ReplaceTokens(String strSourceText) at DotNetNuke.Services.Tokens.TokenReplace.ReplaceTokens(String strSourceText) at DotNetNuke.Services.Tokens.TokenReplace.ReplaceEnvironmentTokens(String strSourceText, ArrayList Custom, String CustomCaption) at DotNetNuke.Services.Localization.Localization.GetSystemMessage(String strLanguage, PortalSettings objPortal, String MessageName, UserInfo objUser, String ResourceFile, ArrayList Custom, String CustomCaption, Int32 AccessingUserID) at DotNetNuke.Services.Mail.Mail.SendMail(UserInfo user, MessageType msgType, PortalSettings settings) at DotNetNuke.Modules.Admin.Users.ManageUsers.PasswordUpdated(Object sender, PasswordUpdatedEventArgs e)

Any suggestions?

I had a similar issue to this.  To fix it i created a new administrator account and assigned it to be the admin account of the site in the "Admin-Site Settings"

Must have been something screwed up with the old amdin account

Hope this helps