KB32888-"There were problems completing this purchase. Please try again or visit BlackBerry App World Support for more information. (Error ID: 30242)" when attempting to complete a purchase in App World on the PlayBook
This is a known issue and is being addressed in a current internal build for the BlackBerry PlayBook OS which is at v2.1.0.1172 right now. No idea when it'll be released or if it will go into a higher version before release but the issue is being worked on, which is always a good thing.