Office 2007 shipped several weights of Arial Narrow but apparently Microsoft made a mistake in the font meta information that causes Adobe products to only recognize Arial Narrow Regular. You can find more information here and also find the relatively painless method of obtaining the hotfix or you can use your crazy-mad ninja skills and search for it. And just in case you’re super lazy:

http://thehotfixshare.net/board/index.php?autocom=downloads&showfile=9298 (not linked on purpose)

Oh, and by the way, after you install the hotfix, quit all Adobe programs, drop to a command-line, cd to root and run the following command to purge the Adobe font cache:

del adobefnt*.lst /S /F