platformlabeler uses os.arch to determine bitness. However, that's not the
OS architecture, but the JRE architecture. For a 64-bit JRE, or a 32-bit
JRE running on a 32-bit OS, you get the right result, but for a 32-bit JRE
running on a 64-bit OS, you don't.

The list of Windows versions is also outdated.

Attached patch works for Windows. Untested for linux, as I don't have a
32-bit linux install available.