Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 1591)
+++ wp-includes/functions.php	(working copy)
@@ -2616,7 +2616,7 @@
 		} else {
 			$wp_smiliessearch .= '|';
 		}
-		$wp_smiliessearch .= preg_quote($rest);
+		$wp_smiliessearch .= preg_quote($rest, '/');
 	}
 
 	$wp_smiliessearch .= ')(?:\s|$)/m';
Index: wp-includes/shortcodes.php
===================================================================
--- wp-includes/shortcodes.php	(revision 1591)
+++ wp-includes/shortcodes.php	(working copy)
@@ -173,7 +173,10 @@
 function get_shortcode_regex() {
 	global $shortcode_tags;
 	$tagnames = array_keys($shortcode_tags);
-	$tagregexp = join( '|', array_map('preg_quote', $tagnames) );
+	static $lamda;
+	if ( !isset($lambda) )
+		$lambda = create_function('$in', 'return preg_quote($in, "/");');
+	$tagregexp = join( '|', array_map($lambda, $tagnames) );
 
 	return '(.?)\[('.$tagregexp.')\b(.*?)(?:(\/))?\](?:(.+?)\[\/\2\])?(.?)';
 }
Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 1591)
+++ wp-includes/formatting.php	(working copy)
@@ -74,8 +74,8 @@
 }
 
 function wptexturize_pushpop_element($text, &$stack, $disabled_elements, $opening = '<', $closing = '>') {
-	$o = preg_quote($opening);
-	$c = preg_quote($closing);
+	$o = preg_quote($opening, '/');
+	$c = preg_quote($closing, '/');
 	foreach($disabled_elements as $element) {
 		if (preg_match('/^'.$o.$element.'\b/', $text)) array_push($stack, $element);
 		if (preg_match('/^'.$o.'\/'.$element.$c.'/', $text)) {
Index: xmlrpc.php
===================================================================
--- xmlrpc.php	(revision 1591)
+++ xmlrpc.php	(working copy)
@@ -3293,7 +3293,7 @@
 
 		$p = explode( "\n\n", $linea );
 
-		$preg_target = preg_quote($pagelinkedto);
+		$preg_target = preg_quote($pagelinkedto, '|');
 
 		foreach ( $p as $para ) {
 			if ( strpos($para, $pagelinkedto) !== false ) { // it exists, but is it a link?
@@ -3315,7 +3315,7 @@
 				$excerpt= str_replace($context[0], $marker, $excerpt); // swap out the link for our marker
 				$excerpt = strip_tags($excerpt, '<wpcontext>');        // strip all tags but our context marker
 				$excerpt = trim($excerpt);
-				$preg_marker = preg_quote($marker);
+				$preg_marker = preg_quote($marker, '|');
 				$excerpt = preg_replace("|.*?\s(.{0,100}$preg_marker.{0,100})\s.*|s", '$1', $excerpt);
 				$excerpt = strip_tags($excerpt); // YES, again, to remove the marker wrapper
 				break;