Comment 1 for bug 1784433

I can confirm that. IMDB sends an error 503. Thats because the URL of the film search page has changed. I will try to provide a patch tomorrow, but meanwhile you can fix this on your own:
Go to the folder, where the program is installed. Then enter into the subfolders lib -> plugins -> movie and open the file PlugInMovieIMDB.py with an editor (notepad, not MS Word, if you happen to use Windows). Search for "def __init__(self)". It is at line 247, if you have the current version. Following are some lines, starting with "#". The next two lines below are key to the problem and its solution.

Replace

        self.original_url_search = 'http://www.imdb.com/find?s=tt&q='
        self.translated_url_search = 'http://www.imdb.com/find?s=tt&q='

with

        self.original_url_search = 'http://www.imdb.com/find?ref_=nv_sr_fn&q='
        self.translated_url_search = 'http://www.imdb.com/find?ref_=nv_sr_fn&q='
but carefully check not to change the indention. It should be the same as before (8 blank spaces)

Thats it. Save and restart Griffith. The new version of the file should automatically trigger the rebuild of the code and you should recieve results from IMDB.