This is what I do...
I'm using XP Pro SP2 (and not gonna change to Windows Vista just to have "beautiful ballons and nice graphics"
, at least, not until Vista gets 2-3 years old) I've got two folders:
Here's is what most people have (default):
- C:/ProgramFiles/VstPlugins (classic root/path)
Now, create a new folder:
- C:/ProgramFiles/
RiffworksPlugins (create that folder just for RW's plugins)
What I do is Installing all the plugins (Gearbox/free ones/Amplitube/ etc...) into the "most common root" which is the 1st I've mentioned (C:/ProgramFiles/VstPlugins)
Then I just copy the *.dll files that belong to the VST's that are more suitable to use with Riffworks and paste them into the new folder created (C:/ProgramFiles/RiffworksPlugins )
Now: Go to the "AMP" tab, press the arrow and select the new Plugin Path created (C:/ProgramFiles/RiffworksPlugins)---> Afaik, a Plugin (VST) is just a *.dll file, then as long as you have them authorized within your Windows Registry (commonly known as "The full packed closet that you should never open, neither try to remove anything, otherwise everything is gonna crumble and fall into pieces

) there won't any issues,
you're not doing anything improperly, just having 2 (or more) Plugin Folders Path where they can be duplicated or suited for each DAW.See? No need to change anything with Riffworks (in that matter), you can have plugin folders to each DAW you use)
E.g.
1 Folder for Audacity
1 Folder for Reaper
1 Folder for Cubase/Sonar/Nuendo
1 Folder for Riffworks!!!
a *.dll is quite light, it's not a 5Gig file, so duplicating is just 5 minutes of your time.
--> In the RWplugins folder created, I reccomend just having:
- Amplitube (all versions that you might've purchased)
- Gearbox Plugin (any version that you might've purchased)
Well, mostly those two ones, you can try to see if other free/purchased VST plugins work well / get along with Riffworks, if they don'twork, just erase the *.dll file named with that plugin from the Riffworks folder, and "refresh" (open & close Riffworks, or - as I prefer - reboot your PC)
Cheers