Same here - running latest CallRecorder build. In the app, it says the same thing. kernel isnt patched or patch is too old. It works though, albeit the other end is a little quiet.
I'm using Chad's Anthrax rev. 13 (latest) which is a VERY common Evo 3D kernel. It def has the 2 way record patch. This is probably the most popular kernel for Evo 3D so this should definitely be looked into. Any ideas on why the app says this?
Also, I wish there was an option in the menu to prevent the CallRecorder service from being started on boot every time. I'd like it to not be running all the time (even with recording disabled) as it's used rarely. Right now, all you can do is manually kill the process and it reloads every time you reset the phone.