tweak to the new fopen mode constant names
diff --git a/system/libraries/Zip.php b/system/libraries/Zip.php
index 6b59880..f7f47ab 100644
--- a/system/libraries/Zip.php
+++ b/system/libraries/Zip.php
@@ -301,7 +301,7 @@
 	 */	

 	function archive($filepath)

 	{

-		if (! ($fp = @fopen($filepath, FOPEN_WRITE_CREATE_BOF)))

+		if (! ($fp = @fopen($filepath, FOPEN_WRITE_CREATE_DESTRUCTIVE)))

 		{

 			return FALSE;

 		}