Fixes cast issue

src/Umbraco.Web/Security/WebSecurity.cs

@@ -250,7 +250,7 @@ namespace Umbraco.Web.Security
             var identity = _httpContext.GetCurrentIdentity();
             if (identity == null)
                 return -1;
-            return (int)identity.Id;
+            return Convert.ToInt32(identity.Id);
         }
 
         /// <summary>

src/umbraco.businesslogic/BasePages/BasePage.cs

@@ -184,7 +184,7 @@ namespace umbraco.BasePages
             var identity = HttpContext.Current.GetCurrentIdentity();
             if (identity == null)
                 return -1;
-            return (int)identity.Id;
+            return Convert.ToInt32(identity.Id);
         }
 
         // Added by NH to use with webservices authentications