I just went though the install process on a new machine running Windows 7 64-bit, and I hit a couple of snags that others might benefit from understanding.
The installer requires a 32-bit JDK. I installed the 64-bit JDK first, and it repeatedly failed to execute the installer properly. Once I installed the 32-bit JDK and pointed my PATH to it, the installer functioned.
Do not attempt to install the tools to anywhere besides the default installation location. The compilers will not function properly. This is becuase, regardless of what you tell the installer, some files end up written to the default location regardless.
The product must be installed in offline mode first, then upgraded using the built-in package updater. Attempting to install off the remote repositories stalls out and never completes.