Email to Admin with Sales Orders stopped.

Two days ago, the email to the Admin notifying of an order stopped sending.  The email of the actual invoice to customer is working fine.  In searching the logs I found the below.

No changes have been made to the code or to the database in months, other than adding a couple of new products.

Any help in resolving this will be greatly appreciated.

Exception of type 'System.Web.HttpUnhandledException' was thrown.  
Exception:  System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.FormatException: Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseDecimal(String value, NumberStyles options, NumberFormatInfo numfmt) at System.Convert.ToDecimal(String value) at NopSolutions.NopCommerce.Web.Modules.OrderDetailsControl.BindData() in E:\new NOPC\Mark\NopCommerceStore\Modules\OrderDetails.ascx.cs:line 151 at NopSolutions.NopCommerce.Web.Modules.OrderDetailsControl.Page_Load(Object sender, EventArgs e) in E:\new NOPC\Mark\NopCommerceStore\Modules\OrderDetails.ascx.cs:line 289 at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) at System.Web.UI.Control.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace --- at System.Web.UI.Page.HandleError(Exception e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.orderdetails_aspx.ProcessRequest(HttpContext context) in c:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\906a0259\55af924b\App_Web_rsnbcd89.13.cs:line 0 at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)