Hi Mitchel and Happy New Year!

I am trying to upgrade a DNN 4.5.5 site to 4.6.2 on the way to upgrading to 4.9.1 but am running into a problem when I try to login. I get the following error:

FormatException: Input string was not in a correct format.]
   System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +2755599
   System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +112
   DotNetNuke.Entities.Users.UserProfile.get_TimeZone() +39
   DotNetNuke.Entities.Users.UserTime.get_ClientToServerTimeZoneFactor() +32
   DotNetNuke.Entities.Users.UserTime.get_CurrentUserTime() +145
   DotNetNuke.UI.Skins.Controls.CurrentDate.Page_Load(Object sender, EventArgs e) +196
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

[PageLoadException: Input string was not in a correct format.]
   DotNetNuke.Services.Exceptions.Exceptions.ProcessPageLoadException(Exception exc, String URL) +376
   DotNetNuke.Framework.PageBase.Page_Error(Object Source, EventArgs e) +483
   System.Web.UI.TemplateControl.OnError(EventArgs e) +2085460
   System.Web.UI.Page.HandleError(Exception e) +71
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +7341
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +213
   System.Web.UI.Page.ProcessRequest() +86
   System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +18
   System.Web.UI.Page.ProcessRequest(HttpContext context) +49
   ASP.default_aspx.ProcessRequest(HttpContext context) +4
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +358
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64

Do you happen to know what is going wrong here? I can successfully display the website in the browser and most everything seems to work with the exception that I cannot log in which, of course. is a show stopper!

Thanks for any help you can give!

Frank