New Post: Paypal showing Status "Payment not verified"

I checked this file : 2014.06.04.log.resources


2014-06-04 03:32:16,847 [PhantomD1][Thread:57][ERROR] DotNetNuke.Services.Exceptions.Exceptions - FriendlyMessage="Error:
<span style="color:red">PLEASE NOTE: Your credit card charge will appear as Always Aware. </span><span style="black">Thank you for your business!
</span> is currently unavailable." ctrl="ASP.desktopmodules_nb_store_checkout_ascx" exc="System.NullReferenceException: Object reference not set to an instance of an object.
at NEvoWeb.Modules.NB_Store.Gateway.GatewayPayPal.StringListReplace(String value, String searchfor, String replacewith)
at NEvoWeb.Modules.NB_Store.Gateway.GatewayPayPal.PayPalEncode(String value)
at NEvoWeb.Modules.NB_Store.Gateway.GatewayPayPal.SetBankRemotePost(Int32 PortalID, Int32 OrderID, String Lang, HttpRequest Request)
at NEvoWeb.Modules.NB_Store.CheckOut.GatewayRedirect()
at NEvoWeb.Modules.NB_Store.CheckOut.Page_Load(Object sender, EventArgs e)"