I had trouble getting GTR Solo to work in Reaper 64 so I wrote to technical support with the error messages I was getting.
Here is the response I got this morning:
Dear Jan,
Thank you for your mail.
Waves is neither compatible nor supported with Reaper.
Please refer to the Tech Specs for more information.
Have a great day.
If you need further assistance feel free to contact us or visit
www.Wavesupport.net
Best Regards,
Yaron Makler
Waves Technical Support Staff
I guess they don't care for the business they might get from this community.