VST Adapter and Windows 7 Solved
I had been dealing with an issue for months with third party plugins not loading in Sonar 4, and I never found the actual solution in any searches. So, I'm posting this just to help anyone who may still be using older versions of Sonar that used the VST adapter program to load plugins.
The issue I was having was that all my third party plugins would not show up in Sonar, even though the VST adapter indicated they should be ready for use. The solution is to run the VST Adapter as an administrator. Right click on the VST adapter shortcut in the start menu and "run as administrator". After doing this, your VST plugins should now appear in your plugins menu in Sonar.
You do not need to run Sonar as an administrator. This was suggested by some, but didn't fix the problem.