Sorry I didn't reply to this sooner - I didn't spot the question.
Anyway, yes the SysWOW64 folder is for DLLs, etc. that are needed for 32-bit programs running under 64-bit Windows, so you would only expect to find it on a 64-bit Windows machine.
On a purely 32-bit machine, you should just need to ensure that an appropriate version of the 32-bit ReWire.dll file is somewhere in the standard search path for all DLLs. There are various places that you could put it, since there are various standard places that Windows will search for any DLL that it tries to load. For example, it searches:
The folder that the application you're running is stored in (this will usually mean the folder containing the .exe file that runs the application);
The system folder (default is usually C:\Windows\system32);
The Windows folder (default is usually C:\Windows);
The current folder when you started the application (usually whatever is specified in the shortcut that runs the application);
plus other places. Individual programs can also specify even more folders or specific locations that they will use when trying to load a DLL.
From the point of view of rewiring Cubase to Reason on a standard 32-bit Windows setup, the easiest and quickest way is probably to ensure that there's a copy of ReWire.dll in C:\Windows\system32. That should allow absolutely any program that tries to run ReWire to find the DLL. If you're on a 32-bit machine, you should only have a 32-bit copy of the DLL (possibly dropped in somewhere like Program Files\Common Files\Propellerhead Software\Rewire by the Reason installer), so there are no worries about possible conflicts between 32-bit and 64-bit versions of the file. Just taking a copy of the ReWire.dll file and dropping it into C:\Windows\system32 should ensure that Cubase can see it and load it when it needs to. (If that doesn't work, something much weirder is going on or your Cubase/Reason installs may be broken somehow.)
[Edit: Hi BeanoBean - just realised that you posted earlier about Nuendo
. Anyway, whatever I've said above should also apply in the case of Nuendo
. So long as the appropriate DLL can be found in one of those places that the system will look for it - and C:\Windows\system32 or its equivalent is usually a safe bet - it should work. I don't really know Nuendo
at all though, so I'm not sure what you'd expect to see when you start it up. Hope it works out anyway.]