--- zipstream.php.orig	2010-10-30 18:57:52.083600724 +0000
+++ zipstream.php	2010-10-30 21:43:45.282800978 +0000
@@ -81,6 +81,7 @@
   var $opt = array(),
       $files = array(),
       $cdr_ofs = 0,
+      $need_headers = false,
       $ofs = 0; 
 
   #
@@ -156,13 +157,14 @@
     $this->opt = $opt;
 
     # set large file defaults: size = 20 megabytes, method = store
-    if (!$this->opt['large_file_size'])
+    if (!isset($this->opt['large_file_size']))
       $this->opt['large_file_size'] = 20 * 1024 * 1024;
-    if (!$this->opt['large_file_method'])
+    if (!isset($this->opt['large_file_method']))
       $this->opt['large_file_method'] = 'store';
 
     $this->output_name = $name;
-    if ($name || $opt['send_http_headers'])
+    if ($name || (isset($opt['send_http_headers']) 
+        && $opt['send_http_headers']))
       $this->need_headers = true; 
   }
 
@@ -293,7 +295,7 @@
     $nlen = strlen($name);
 
     # create dos timestamp
-    $opt['time'] = $opt['time'] ? $opt['time'] : time();
+    $opt['time'] = isset($opt['time']) ? $opt['time'] : time();
     $dts = $this->dostime($opt['time']);
 
     # build file header
@@ -499,12 +501,12 @@
     
     # grab content type from options
     $content_type = 'application/x-zip';
-    if ($opt['content_type'])
+    if (isset($opt['content_type']))
       $content_type = $this->opt['content_type'];
 
     # grab content disposition 
     $disposition = 'attachment';
-    if ($opt['content_disposition'])
+    if (isset($opt['content_disposition']))
       $disposition = $opt['content_disposition'];
 
     if ($this->output_name)