Make sure you update to the latest version!! ADOBE AUTO UPDATER WILL NOT DO THIS. Use these links:
Mac: https://www.adobe.com/support/downloads/product.jsp?product=98&platform=Macintosh
PC: https://www.adobe.com/support/downloads/product.jsp?product=98&platform=Windows
I had a nightmare for a while after upgrading and reinstalling osx where all AVCHD projects that had been fine stopped playing pack and crashing premiere. Upgrading CS4 to 4.2.1 seemed to fix this :).