See http://pecl.php.net/bugs/bug.php?id=7276

--- pop3.c.orig	2010-01-11 00:18:21.000000000 +0100
+++ pop3.c	2010-01-11 00:18:31.000000000 +0100
@@ -172,8 +172,7 @@
 
 	intern = emalloc(sizeof(pop3_object));
 	intern->zo.ce = class_type;
-	intern->zo.in_get = 0;
-	intern->zo.in_set = 0;
+	intern->zo.guards = NULL;
 	intern->zo.properties = NULL;
 	intern->ptr = NULL;
 
