I purchased Pearl Harbor as well and received the same error code (-50) when it finished downloading and began processing.
I contacted Apple iTunes support by accessing my account in the iTunes store, selecting 'Purchase History', then selecting 'Report a problem', selecting the video item and reporting the error.
I received an email the next day from iTunes Store Customer Support with instructions on how to troubleshoot the problem:
I'm sorry to hear that "Pearl Harbor" did not download properly. I know that must be frustrating, and I am happy to help.
I have re-posted the movie to your account. Please follow these steps to download the item:
1) Make sure you're using the latest version of iTunes. It can be downloaded free of charge:
http://www.apple.com/itunes/download
Note: Installing the latest version of iTunes will not affect your Library or any items in your account that you haven't downloaded.
2) From the pull-down Store menu at the top, select Check for Purchases (if you're unable to upgrade and are using iTunes 6 or earlier, you'll find this option in the Advanced menu). If you can't find this option, you can also click this link to Check for Purchases:
https://phobos.apple.com/WebObjects/MZFinance.woa/wa/checkForPurchases
Enter your account name and password, then click Check. The missing item should begin downloading and appear in your Purchased playlist.
If you receive an error message while downloading, try again after turning off any firewall or web-accelerator software that you may have installed.
If the download process is interrupted for any reason, it should resume once you reopen iTunes.
This article provides information about resuming interrupted downloads:
http://www.info.apple.com/kbnum/n93015
In the future, you can resolve some purchasing difficulties more efficiently by using the new "Report a Problem" feature of the iTunes Store. To do this, simply sign in to the iTunes Store and click Account in the QUICK LINKS list. In the Account Information page, click Purchase History, then click the Report a Problem button. Finally, click the Report a Problem link to the right of the item in question and follow the onscreen instructions.
As to the error message you are receiving , these instructions may help you resolve this issue:
1) Open iTunes.
2) From the Store menu, choose Deauthorize Computer. Enter your account name and password and click OK.
3) Once your computer has been deauthorized, choose "Check for Purchases" from the Store menu. Enter your account name and password and click OK. Your purchases should begin downloading. Once downloaded, they will appear in your Purchased playlist as well as in your iTunes Library.
If your purchases download successfully, you will need to reauthorize your computer before you can play them. To do this, choose Authorize Computer from the Store menu, enter your account name and password, and click OK.
That should get you back on track, so you can enjoy the movie. Thank you for choosing the iTunes Store. Apple truly appreciates your business.
Sincerely,
iTunes Store Customer Support
I followed the instructons, but the same thing happend. It still has not worked.
I strongly doubt it is my firewall. Earlier in the week, I purchased and downloaded 'Pirates Of The Caribbean: Dead Man's Chest' easily without any errors while my firewall being enabled.
I have reported the error again and am waiting for an answer from iTunes support.
Sony Windows XP 