Make sure that default.htm is referenced via a chrome: URL.

suite/common/search/internetresults.js

@@ -72,7 +72,7 @@ function doEngineClick(node)
 	}
 	else
 	{
-		window.frames[0].document.location = "default.htm";
+		window.frames[0].document.location = "chrome://search/content/default.htm";
 	}
 
 }

suite/common/search/internetresults.xul

@@ -76,7 +76,7 @@
 	</tree>
 
 	<splitter id="searchHtmlAreaSplitter" persist="state" style="border-top:solid black 1px; border-bottom:solid black 1px; background-color:lightgray;" collapse="after" />
-	<html:iframe id="content" type="content-primary" style="height: 100; width: 100%;" flex="100%" src="resource:/res/samples/default.htm" />
+	<html:iframe id="content" type="content-primary" style="height: 100; width: 100%;" flex="100%" src="chrome://search/content/default.htm" />
 
 <!--
 This extra "status" bar is necessary because the bottom right corner of the window on MacOS is

xpfe/components/search/resources/internet.js

@@ -278,7 +278,7 @@ function doSearch()
 	if (contentArea)
 	{
 		contentArea.setAttribute("style", "height: 100; width: 100%;");
-		parent.frames[1].frames[0].document.location = "default.htm";
+		parent.frames[1].frames[0].document.location = "chrome://search/content/default.htm";
 	}
 
 	// enable "Save Search" button

xpfe/components/search/resources/internetresults.js

@@ -72,7 +72,7 @@ function doEngineClick(node)
 	}
 	else
 	{
-		window.frames[0].document.location = "default.htm";
+		window.frames[0].document.location = "chrome://search/content/default.htm";
 	}
 
 }

xpfe/components/search/resources/internetresults.xul

@@ -76,7 +76,7 @@
 	</tree>
 
 	<splitter id="searchHtmlAreaSplitter" persist="state" style="border-top:solid black 1px; border-bottom:solid black 1px; background-color:lightgray;" collapse="after" />
-	<html:iframe id="content" type="content-primary" style="height: 100; width: 100%;" flex="100%" src="resource:/res/samples/default.htm" />
+	<html:iframe id="content" type="content-primary" style="height: 100; width: 100%;" flex="100%" src="chrome://search/content/default.htm" />
 
 <!--
 This extra "status" bar is necessary because the bottom right corner of the window on MacOS is