ITunes For Mac :: 12.0.1 Crashes At End Of Movie Download From Store

I have a Mid-2011, 21.5" iMac running Yosemite v10.10.1.  I upgraded from 4 to 8 GB of RAM about a year ago, but I don't think that's an issue with this problem. 

I can no longer download movie or tv show purchases from the iTunes Store to iTunes v12.0.1 on my iMac.  The download starts and lists in the Downloads pane in iTunes.  However, once the download has completed and the Download progress bar message changes to "Processing..." iTunes crashes.  When I start iTunes back up again, the downloaded movie is not present in my iTunes Movie library.  However, if I navigate to the iTunesMovies folder, I can see a folder for the movie and a file instance of the movie (in m4v format) for every attempted download.  Something seems to be going wrong with iTunes ability to add the link to the movie file into my iTunes library. 

I tried adding the movie folder and file manually to iTunes using the iTunes->File->Add to Library... menu option, but iTunes instantly crashes the moment I click the "Open" button in the Add to Library... dialog window. 

I have several movie purchases and gifts that I'd like to add to my local iTunes library, but this error is blocking me from doing that.

Some weird things about my iTunes library on my iMac:

My iMac does not have a large enough built-in harddrive (only 500 GB) to store my iTunes library.  In a prior version of iTunes, I located the library on an external 3 TB USB-3.0 harddrive.  I'm wondering if there's a bug in iTunes 12.0.1 that occurs when adding content to the iTunes library when that content is located on an external harddrive, i.e. in a folder other than User{my username}MusiciTunes Media.  Perhaps I need to change the iTunes folder structure on the external harddrive to mirror the new folder structure in my User{my username}Music folder.  I'm a little leery about doing this as I do not want to break all the links in my iTunes library to existing songs, movies, etc. 

Info:
iMac, OS X Yosemite (10.10.1)