Found an answer for you on the Reaper forum.
The guy had the same problem but then found the following fix
The fix was:
- explicitly add C:\Program Files (x86)\Waves as a VST search path, rather than C:\Program Files (x86)\Waves\Plug-Ins
Hope this helps!
You mean put all of my C:\Program Files (x86) into my VST folder ?
NO. ABSOLUTELY DO NOT DO THIS.
If you are somehow able to launch mixcraft, you will need to go into settings and the VST panel, and add the correct search path.
DO NOT MOVE YOUR PROGRAM FILES FOLDER. THAT'S A RIDICULOUSLY STUPID MOVE THAT HAS SOME SERIOUSLY BAD CONSEQUENCES.
actually, in theory you should be able to continue to open mixcraft without the missing dll. I'm able to launch mixcraft, and I get two separate "missing .dll" errors every time I start it up, and it still loads fine.