Just some extra info:
I installed the Reason 6.5 demo (before l purchased it) on my other 32-bit Windows XP computer.
Was able to make Ableton 8 (on that same computer) the Rewire slave of Reason 6.5.2 (not 6.5.3). Lovely.
However, as l mentioned, and as the original post mentioned, Rewire won't work between Reason 6.5.3 and Acid Pro 7. I suspect it's got something to do with the computer l'm using it on: a 64-bit Windows 7 laptop. And of course, Acid Pro 7 is 32-bit. Just to recap: recording "what you hear" is also not working for Audacity on this 64-bit computer.
Unfortunately l've only got 2 GB free HD space on my 32-bit computer, so l will have to wait a few days before l can move over to that computer and try the Reason 6.5.3 / Acid Pro 7 Rewire combination.
I suspect this isn't a Reason problem ... it's just the whole thing about 64-bit Windows. And, as someone mentioned, the mismatch in 64-bit / 32-bit software. There seems to be something fundamentally wrong with 64-bit processor architecture, because l've noticed that other non-music programs have been said to flounder on 64-bit Windows OS. So l think the problem is 64-bit processor architecture and / or 64-bit Windows OS.
We're in the space age now and still being tripped up by blatant stuff like this! People should test computers / OSes before rolling them out. I wish Reason would make an official comment on the situation.
Extra info: Rewire doesn't seem to work between Acid Pro 7 (32-bit) and Renoise (not Reason) 32-bit, on this 64-bit Windows 7 laptop. I now think it's not so much to do with the mismatch in 64-/32-bit software, as the actual 64-bit Windows 7 OS and / or 64-bit processor architecture. The problem seems to be somewhere there.
Final edit: One more possibile cause is the mismatch between 32-bit software and 64-bit [Windows / Windows 7] OS.
Last edited by DynamicDontPanic; 2013-02-18 at 04:12.