The Waves plug-ins have been an issue that I'm sure many have had, including myself. I've addressed this with Cakewalk and Waves, and neither seem to know the best answer, unfortunately.
Waves mentioned to me that this is due to the fact that the install deploys both 32 and 64-bit plug-ins, regardless of your need, which I believe is a seriously BAD decision on their part, but Sonar does something that is very irritating as well here. It tends to hold exact plug-in versions "hostage" and will cause you lots of grief, if you upgrade minor versions/iterations in the Waves train.
The best solution isn't in the works, I'm expecting. I think the only way this one will be worked out is when all 32-bit installations are no longer, Waves has gone to v10, which may not include 32-bit plug-ins, and Sonar is at least somewhat more tolerant with 3rd-party plugs.
I was surprised, myself at how many bugs and crashes Sonar X1 and X2 had/have when I bought into the line. I still feel the burn. But, I'm hoping X2b will finally be the best, most stable version ever. As I've wished in other threads, I want to see that above everything else.
My perception of Cakewalk is under-staffed, over-worked, and feature-driven. And I know their teams don't like seeing us fuss about their hard, HARD work.
My Waves Solution: When installing the Waves plug-ins, make sure you set your 32-bit plug-ins location to some arbitrary and very hidden directory so that Cakewalk can't find them. Otherwise, it's like letting a baby have access to pretzels. He'll choke on them. Not meant as an insult to Cakewalk or Waves, but some things are better kept apart.