The IIS7 - Tomcat6 Connector howto should give a hint, that in 64bit environment the used IIS Application Pool should have "Enable 32-bit Applications" set to "False". Otherwise the isapi redirect will not be called and returns an http code 404. If you think, the 32bit version of isapi_redirect.dll would do the job instead, you will get an http code 500, because the library is not loadable.
Thanks for the information. Fixed in r1187956. Regards, Rainer
Note that the live documentation is usually only updated after a new release. The new info will be part of version 1.2.33.