Can't you just uninstall Trilogy completely and then reinstall it...letting it put the files where it wants? Or do you have space limitations on your drives?

No...
 
 
Im not reinstalling, it, Ive done that 20 times and it only helped...
 
 
WHERE do I allocate the files? the .DAT, and .dll?  WHERE
 
Very simple ****ing question.

stupid ass answer, uninstall and reinstall? thats so stupid!

Thanks for the compliment, ol stick. But 999999999.9 times out of eleventy jillion the error lies with the nitwit that's trying to install it. I don't expect this case is any different. As you may note above the OPs problem WAS solved by uninstalling and then reinstalling CORRECTLY. Something you might consider. Or not.

This is an old thread, but I wanted to add my experience here just in case anyone is looking to use their old version of Spectrasonics Trilogy with Sonar Premium on Windows 7 64bit.
I recently downgraded to a W7 laptop so as to use an old Firewire soundcard (I might upgrade to W10 again as there are stability problems). As part of the downgrade I decided to reinstall my old version of Trilogy and encountered the same problem other people had in this thread. Here's how I resolved the issue.
 
1. Install Trilogy from CDs using Admin rights.
2. Install the Trilogy.dll file to C: drive (this is the 3,284kb file.
3. Once installed, make a folder in C: called 'Trilogy'. Path: C:\Trilogy
4. Drag and Drop .dll file into Trilogy folder. You don't need Spectramove.
5. In Platinum, open Cakewalk Plugin Manager.
6. in the box 'VST Configurations', select 'Options'.
7. In new box, click 'Add...' and select C:\trilogy
8. Click OK
9. In 'VST Configurations', select 'Scan VST Plug-ins'
10. Your SONAR Platinum should now recognise Trilogy as a VST instrument called 'Trology stereo2stereo'.
11. You might have to unlock Trilogy via the Spectrasonics website.
 
This method worked for me and allowed me to use my old Trilogy with its cool acoustic basses.
 
Hope this helps.
P