here are some more detail on the error.
this is taken from my portals events viewer

Message: DotNetNuke.Services.Exceptions.PageLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at DotNetNuke.Services.Localization.TokenReplace.calc(String strObjectName, String strPropertyName, String strFormat, ArrayList Custom, DataRow Row) at DotNetNuke.Services.Localization.TokenReplace.ReplaceEnvironmentTokens(String strSourceText, ArrayList Custom, DataRow Row) at DotNetNuke.Services.Localization.Localization.GetSystemMessage(String strLanguage, PortalSettings objPortal, String MessageName, UserInfo objUser, String ResourceFile, ArrayList Custom) at DotNetNuke.Services.Mail.Mail.SendMail(UserInfo user, MessageType msgType, PortalSettings settings) at DotNetNuke.Modules.Admin.Users.ManageUsers.ProfileUpdateCompleted(Object sender, EventArgs e) at DotNetNuke.Entities.Modules.ProfileUserControlBase.OnProfileUpdateCompleted(EventArgs e) at DotNetNuke.Modules.Admin.Users.Profile.cmdUpdate_Click(Object sender, EventArgs e) at DotNetNuke.UI.WebControls.CommandButton.RaiseClick(Object sender, EventArgs e) at System.Web.UI.WebControls.LinkButton.OnClick(EventArgs e) at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---