iTunes freezing when accessing Media folder located on NAS

I'm running the latest version of iTunes on Windows 7 (64bit)

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My Media is located on a QNAP TS412 NAS.

I have a desktop machine that accesses the Media without issue.

However, when I launch iTunes on my laptop after a short while the application will freeze.

If however, I point iTunes to a media folder on the local hard drive no problems are encountered. Any ideas?