Can't start new thread

[ardianta]

Hi, I got error like this at the middle of downloading process...

Traceback (most recent call last):
  File "tumblrdownloader.py", line 177, in <module>
    main(sys.argv[1:])
  File "tumblrdownloader.py", line 169, in main
    td.download()
  File "tumblrdownloader.py", line 105, in download
    self._downloadimage(imagelist)
  File "tumblrdownloader.py", line 137, in _downloadimage
    t.start()
  File "/usr/lib/python2.7/threading.py", line 736, in start
    _start_new_thread(self.__bootstrap, ())
thread.error: can't start new thread