Mark Favas points out that there's an 'self.fp.flush()' call in the

ZipFile.close() method that should be part of the preceding 'if'
block.  On some platforms (Mark noticed this on FreeBSD 4.2) doing a
flush() on a file open for reading is not allowed.

Lib/zipfile.py

@@ -468,7 +468,7 @@ class ZipFile:
             endrec = struct.pack(structEndArchive, stringEndArchive,
                      0, 0, count, count, pos2 - pos1, pos1, 0)
             self.fp.write(endrec)
-        self.fp.flush()
+            self.fp.flush()
         if not self._filePassed:
             self.fp.close()
         self.fp = None