Index: load.php
===================================================================
--- load.php	(revision 13211)
+++ load.php	(working copy)
@@ -82,6 +82,15 @@
 	$PHP_SELF = $_SERVER['PHP_SELF'];
 	if ( empty( $PHP_SELF ) )
 		$_SERVER['PHP_SELF'] = $PHP_SELF = preg_replace( "/(\?.*)?$/",'',$_SERVER["REQUEST_URI"] );
+		
+		
+	/**
+	 * global $_SERVER array initialisation if certain indexes are not used
+	 * to prevent warnings on all requests.
+	 */	
+	foreach ( array( 'HTTP_HOST', 'REQUEST_URI', 'SERVER_SOFTWARE' ) as $var )
+		if ( !isset($_SERVER[$var]) )
+			$_SERVER[$var] = '';
 }
 
 /**
Index: theme.php
===================================================================
--- theme.php	(revision 13211)
+++ theme.php	(working copy)
@@ -624,7 +624,7 @@
 	if ($stylesheet_or_template) {
 		$theme_roots = get_theme_roots();
 
-		if ( $theme_roots[$stylesheet_or_template] )
+		if ( !empty( $theme_roots[$stylesheet_or_template] ) )
 			$theme_root = WP_CONTENT_DIR . $theme_roots[$stylesheet_or_template];
 		else
 			$theme_root = WP_CONTENT_DIR . '/themes';