Registry Weirdness--SOLVED

So I finally get Sonar PE 8.5 x64 up and running on Windows 7 RTM, and copy some of my projects into my new project folder. I open one. Sonar promptly complains that the registry key is different and offers me a choice of Kontakt 3 (x86) or Kontakt 3 x64. I choose the second. Kontakt complains it can't find the samples, fine, I locate them (gonna post about this on NI forum; it should be able to find them in the new location with the library and database properly set as they are).
The project opens and I see it has loaded Guitar Rig 4 (x86) instead of GR4 x64. I delete the 32-bit version and insert the 64-bit one. Screen freeze. I finally had to create a new project and insert the instruments manually. Fortunately it was a project in its earliest stages so I only had to copy and paste one MIDI track from the old to the new one.
OK, so the project file could have become corrupted. I'll see what happens with my other projects as I go along.
But I don't understand this registry stuff. Shouldn't Sonar be able to find Gutar Rig 4 with its new registry key (it shows up in Plugin Manager)?

update: see below

Would that it were that simple--this project was created in 64-bit, using the aforementioned plugins' 64-bit version. That's why I don't getit...

Yep! I had started the project while I was running Win 7 RC x64,  and had inserted Kontakt 3.5 and Gr4 as 64-bit VSTs. Loading the same project a month and a half later in Win 7 RTM x64, first Sonar pops up a box complaining about the K3 registry key being wrong and offering me a choice of the 32-and 64-bit plugin. A minor nuisance, I chose the 64-bit one. But as far as GR4 goes, it did insert it as a 32-bit VST (without giving me the same choice) all on its own...that's why I said "weirdness">
I had something similar-but-different happen between the first and second installs of Win 7 RC x64. On the second install, when I changed the GR plugin properties to "configure as synth" (so I could assign a midi track to control the pedals) GR3 and GR4  disappeared fromPlugin Manager altogether. I found out the registry still said "configure as synth = 0" and changed that to 1, and got them back.
This time, at lease they still show after I make that change. I just have to be careful loading "old" projects...something must have happened to the project file too, though, cos it shouldn't have frozen when I took out the 32-bit GR4 and inserte the 64-bit one. I hope that doesn't happen with all my previous projects.
I'm told one can bounce projects back and forth between Sonar 64-bit and 32-bit (on the same machine). I wonder if people who do that do about the different versions of the plugins (the 64-bit project would use the 64-bit versions, so would the 32-bit project know to load them, or not?).

Actually, I hope I can't. But if it keeps happening with my pre-Win 7 RTM projects, I should certainly have something I can send to CW...

No, this is a confusion in the registry (seemingly unique to me--ain't I lucky?) between 32-bit plugs and 64-bit plugs....there's a list on the forums of plugins that are known to work with 64-bit and ones people have trouble with. I'll post back with it (the forum search engine stinks on ice) but you should be able to get your plugins to work. Worst case scenario, you can install Sonar 32-bit as well (it lives in its own folders, no problem) and open the 32-bit plugins there.

...if that doesn't do it, check out jBridge. A lot of folks here are using it to bridge plugins that BitBRidge may miss. Also, if the plugins you want are DXi, DxiShell works, I've tried it.
If you want to go 64-bit, though you should upgrade to 8.5...BitBridge has changed a lot since the ealy 64-bit days. It may do the job all by itself; depends what plugs you're talking about.