Hi. I have just bit the bullet and upgraded my pc to a intel i3 64bit running windows 7 64bit os. I now use cubase 5.5 64bit as my main daw As well as reason 6 and I have noticed that the rewire option is not available to me any more.
When I had the 32bit cubase there was no problem yet I find it strange that the 64bit will not work.
Any help would be appreciated…
Thanks…
Rewire does not operate on 64 bit versions of Cubase (except 6.0.6 and up/6.5 and up). So basically you have to run it in 32 bit mode or bite another bullet and upgrade to C6. 
Not sure if Reason 6 is 64bit, but if it’s not, don’t bother upgrading to Cubase 6.5.
I made the mistake thinking I could do the same thing with Acid Pro7, then realized that all software you have has to be 64bit. So for now, I’m running C in 32bit if I want to use Acid, or Reason 4.
Thanks for your replys, I thought as much but the strange thing now is the rewire option is in the devices menu and was not there before. When I try and load reason a message says Rewire installation failed because access to a file or directory was denied while installing the rewire dll in the system directory.
Are you having these problems while running the 32 bit version? If you aren’t desperate for more RAM or dealing with huge projects, I would go run the 32 bit version again, until you were to upgrade Cubase.