fixed not found page problem

docs/changelog/6.x.x.txt

@@ -1,4 +1,6 @@
 6.7.0
+ - Fixed a potential problem where editing a page under rare very rare 
+   conditions could destroy the not found page.
  - Added the ability to override the UI Level of any field in the edit form of
    any asset in the WebGUI config file.
  - Translation providers can now add languageAbbreviation and locale

lib/WebGUI.pm

@@ -89,6 +89,7 @@ sub page {
 	my $output = _processOperations();
 	if ($output eq "") {
 		my $asset = WebGUI::Asset->newByUrl($assetUrl);
+		if (defined $asset) {
 			$session{asset} = $asset;
 			my $method = "view";
 			if (exists $session{form}{func}) {
@@ -104,6 +105,9 @@ sub page {
 					$output = $asset->www_view;
 				}
 			}
+		} else {
+			$output = WebGUI::Asset->getNotFound->www_view;
+		}
 	}
 	WebGUI::Affiliate::grabReferral();	# process affilliate tracking request
 	if (WebGUI::HTTP::isRedirect() && !$useExistingSession) {

lib/WebGUI/Asset.pm

@@ -1056,7 +1056,8 @@ sub newByUrl {
 		if ($id ne "" || $class ne "") {
 			return WebGUI::Asset->new($id, $class, $version);
 		} else {
-			return WebGUI::Asset->getNotFound;
+			WebGUI::ErrorHandler::warn("The URL $url was requested, but does not exist in your asset tree.");
+			return undef;
 		}
 	}
 	return WebGUI::Asset->getDefault;