Installing the BlackBerry PlayBook SDK  will fail on Windows 7 if a 64-bit JVM is installed on the system with an error saying “Win64 not supported”.
An easy way to get the SDK to install is to force the installer to use a 32-bit JDK.  This can be done by unzipping the installer.  When unzipped, there are two folders (InstallerData and Windows) that are extracted.  Inside the Windows folder, edit the file BlackBerryTabletSDK-Air-Installer-  Inside this file is a line that reads: 
Edit this line to point to the javaw.exe executable in a 32-bit JVM you have installed.  e.g. Files (x86)/Java/jdk1.6.0_20/bin/javaw.exe 
Once you have done that, run the installer (BlackBerryTabletSDK-Air-Installer- from the Windows directory and the SDK will install correctly on 64-bit Windows.