I would also HIGHLY suggest turning off JavaScript support in Acrobat.. No standard PDF's anywhere use them and it slows down (or hangs) Acrobat 6.0 from opening if you use the latest Sun Desktop Java,
Go to Edit, Preferences, JavaScript (within Acrobat) and take the checkmark off "Enable Acrobat JavaScript" Also selecting "Startup, and disabling Splash + Messages causes a slight load time improvement as well.
One more, removing a PDF viewed via IE will cause IE and Acrobat to be more stable... This is done under Edit, Preferences, Internet, Remove "Display PDF in Browser"