That note applies to the fact that on Windows we ONLY compile and provide a 32 Bit mod_inomads.so for Apache 2.2 and 2.4. You can safely recompile the mod_inomads module yourself as we provide the source however you will require a 'C' compiler and to download the Apache development source headers for Windows.
For Linux, Aix, Unix, and MacOS you would compile the source based on the OS and hardware you are running on using the OS supplied 'C' compilers using the apxs command that comes with Apache.
Note you can mix 32 and 64 bit Apache and PxPlus (i.e. You can use the 32 bit Apache with either the 32 or 64 bit PxPlus on Windows).